feat: group SSH config directives with trade-off explanations

SSH config hardening now presents directives in logical groups
(matching the git config UX) with reasoning for each:
- Host Verification: TOFU rationale, known_hosts exfiltration risk
- Key & Agent Management: key enumeration attack, passphrase fatigue
- Algorithm Restrictions: downgrade attack, intentional RSA breakage

Each group batches its directives into a single prompt instead of
asking one-by-one.

Bump version to 0.3.1.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

CHANGELOG.md

@@ -4,7 +4,37 @@ All notable changes to this project will be documented in this file.
 
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 
-## [0.1.0] - 2026-03-31
+## [0.2.3] - 2026-03-31
+
+### Fixed
+- FIDO2 key generation on macOS — detect Homebrew's openssh via `ssh-sk-helper` (no freeze), use its `ssh-keygen` binary for hardware key generation
+- Linux gitleaks install hint now shows `apt`/`dnf` instead of `brew`
+- e2e test runner distro loop broken by `IFS` setting — use bash array
+
+### Changed
+- Group interactive apply prompts into 6 categories with one-line explanations (replaces ~25 individual prompts)
+
+## [0.2.0] - 2026-03-31
+
+### Added
+- Gitleaks pre-commit hook installation — creates `~/.config/git/hooks/pre-commit` with `SKIP_GITLEAKS` bypass
+- Global gitignore creation (`~/.config/git/ignore`) with security patterns (`.env`, `*.pem`, `*.key`, credentials, Terraform state)
+- Audit of existing global gitignore for missing security patterns
+- 8 new git config settings: `user.useConfigOnly`, `protocol.version=2`, `transfer.bundleURI=false`, `init.defaultBranch=main`, `core.symlinks=false` (interactive-only), `fetch.prune=true`, `gc.reflogExpire=180.days`, `gc.reflogExpireUnreachable=90.days`
+- Combined signing enablement into single prompt (replaces 3 individual prompts)
+- 26 new BATS tests (90 total)
+
+### Security
+- SSH key hygiene audit — scans `~/.ssh/*.pub` and `IdentityFile` entries, warns about DSA/ECDSA/weak RSA keys
+- Plaintext credential file detection — warns about `~/.git-credentials`, `~/.netrc`, `~/.npmrc` (auth tokens), `~/.pypirc` (passwords)
+- `safe.directory = *` wildcard detection and removal (CVE-2022-24765)
+
+### Fixed
+- `ssh-keygen` calls fail on macOS with `--` end-of-options separator (removed)
+- Interactive tests fail on macOS due to tmux resetting `HOME` in login shells
+- Interactive tests race condition with tmux session cleanup between tests
+
+## [0.1.0] - 2026-03-30
 
 ### Added
 - Interactive shell script that audits and hardens global git config
@@ -32,5 +62,3 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 - SSH config value parsing handles inline comments and quoted paths
 - Version comparison uses base-10 arithmetic to prevent octal interpretation
 - Temp file cleanup trap in SSH config updates
-- `--` separator before path arguments in `ssh-keygen` calls
-- Removed unused exported `SIGNING_KEY_PATH` variable

README.md

@@ -38,16 +38,23 @@ The script runs in two phases:
 
 | Category | What it does |
 |---|---|
-| **Object integrity** | Validates all objects on fetch/push/receive (`transfer.fsckObjects`, etc.) |
-| **Protocol restrictions** | Default-deny policy: only HTTPS and SSH allowed. Blocks `git://` (unencrypted) and `ext://` (arbitrary command execution) |
-| **Filesystem protection** | Enables `core.protectNTFS`, `core.protectHFS`, disables `core.fsmonitor` |
+| **Identity** | `user.useConfigOnly=true` — prevents commits without explicit identity |
+| **Object integrity** | `fsckObjects` on transfer/fetch/receive, `transfer.bundleURI=false`, `fetch.prune=true` |
+| **Protocol restrictions** | Default-deny policy: only HTTPS and SSH. Blocks `git://` and `ext://`. Forces `protocol.version=2` |
+| **Filesystem protection** | `core.protectNTFS`, `core.protectHFS`, `core.fsmonitor=false`, `core.symlinks=false` (interactive-only) |
 | **Hook control** | Redirects `core.hooksPath` to `~/.config/git/hooks` so repo-local hooks can't execute |
-| **Repository safety** | `safe.bareRepository=explicit`, `submodule.recurse=false` |
-| **Pull/merge hardening** | `pull.ff=only`, `merge.ff=only` — refuses non-fast-forward merges, surfacing rewritten history |
+| **Pre-commit hook** | Installs gitleaks secret scanner as global pre-commit hook (with `SKIP_GITLEAKS` bypass) |
+| **Repository safety** | `safe.bareRepository=explicit`, `submodule.recurse=false`, detects/removes `safe.directory=*` wildcard |
+| **Pull/merge hardening** | `pull.ff=only`, `merge.ff=only` — refuses non-fast-forward merges |
 | **Transport security** | Rewrites `http://` to `https://`, enforces `http.sslVerify=true` |
 | **Credential storage** | Platform-detected secure helper (`osxkeychain` on macOS, `libsecret` on Linux). Warns if using plaintext `store` |
+| **Credential hygiene** | Warns about plaintext `~/.git-credentials`, `~/.netrc`, `~/.npmrc` (tokens), `~/.pypirc` (passwords) |
+| **Global gitignore** | Creates `~/.config/git/ignore` with patterns for secrets, credentials, and OS/IDE artifacts |
+| **Defaults** | `init.defaultBranch=main` |
+| **Forensic readiness** | Extended reflog retention (`gc.reflogExpire=180.days`, `gc.reflogExpireUnreachable=90.days`) |
 | **Commit signing** | SSH-based signing with interactive key setup wizard (software or FIDO2 hardware key) |
 | **SSH hardening** | `StrictHostKeyChecking=accept-new`, `HashKnownHosts=yes`, `IdentitiesOnly=yes`, modern algorithm restrictions |
+| **SSH key hygiene** | Audits `~/.ssh/*.pub` for weak key types (DSA, ECDSA, short RSA) |
 | **Visibility** | `log.showSignature=true` |
 
 A config backup is saved to `~/.config/git/pre-harden-backup-<timestamp>.txt` before any changes.
@@ -95,6 +102,7 @@ Options:
 - Bash 3.2+ (compatible with macOS default bash)
 
 Optional:
+- `gitleaks` for pre-commit secret scanning (hook is installed regardless; scans run only if gitleaks is on `$PATH`)
 - `ykman` or `fido2-token` for FIDO2 hardware key detection
 
 ## Threat Model
@@ -106,9 +114,11 @@ Optional:
 - **Protocol downgrade** — blocks plaintext `git://` and dangerous `ext://` protocol
 - **Hook-based RCE** — redirects hook execution away from repo-local `.git/hooks/`
 - **Submodule attacks** — disables auto-recursion; submodules must be explicitly initialized
-- **Credential theft** — ensures secure credential storage, warns about plaintext `store`
+- **Credential theft** — ensures secure credential storage, warns about plaintext `store`, detects leaked credentials in `~/.git-credentials`, `~/.netrc`, `~/.npmrc`, `~/.pypirc`
+- **Secret leakage** — gitleaks pre-commit hook blocks commits containing secrets before they enter git history
 - **Commit impersonation** — SSH signing proves key possession (anyone can fake `user.name`/`user.email`)
-- **Filesystem tricks** — blocks NTFS/HFS+ path manipulation attacks
+- **Filesystem tricks** — blocks NTFS/HFS+/symlink path manipulation attacks
+- **Weak SSH keys** — audits and warns about DSA, ECDSA, and short RSA keys
 
 ### What this does NOT protect against
 
@@ -132,14 +142,30 @@ The script prints (but does not apply) server/org-level recommendations:
 ## Running Tests
 
 ```bash
-# Run the BATS test suite (64 tests)
+# Init test framework submodules (first time only)
+git submodule update --init --recursive
+
+# Unit tests (BATS) — runs in isolated $HOME, never touches real config
 ./test/run.sh
 
-# Requires bats-core submodules — init them if needed
-git submodule update --init --recursive
+# Interactive tests (tmux) — tests the full interactive flow on macOS/Linux
+./test/run-interactive.sh
+
+# Full e2e matrix — containers + interactive tests across distros
+# Requires docker or podman
+./test/e2e.sh                                    # All distros + host
+./test/e2e.sh --skip-host ubuntu                 # Single distro, skip host
+./test/e2e.sh --runtime podman --skip-host       # All distros via podman
+./test/e2e.sh --rebuild alpine                   # Force image rebuild
 ```
 
-Tests run in an isolated `$HOME` (via `mktemp`) and never touch your real git or SSH config.
+| Test tier | What it covers | Requirements |
+|-----------|---------------|--------------|
+| `test/run.sh` | 92 BATS unit tests — config audit, apply, signing, key detection | `bats-core` submodule |
+| `test/run-interactive.sh` | 4 tmux-driven tests — full accept, safety gate, signing wizard | `tmux` |
+| `test/e2e.sh` | Container matrix (Ubuntu, Debian, Fedora, Alpine, Arch) + host interactive | `docker` or `podman` |
+
+All tests run in isolated environments and never modify your real git or SSH configuration.
 
 ## License
 

docs/REASONING.md

@@ -0,0 +1,397 @@
+# Reasoning: Why Each Default Was Chosen
+
+Every setting `git-harden.sh` audits or applies exists because of a specific attack vector or operational risk. This document explains the trade-off behind each one.
+
+Settings are grouped the same way they appear in the script's audit output.
+
+---
+
+## Identity
+
+### `user.useConfigOnly = true`
+
+**What it does:** Prevents git from falling back to system-level identity (hostname, login name) when `user.name` and `user.email` aren't set in `.gitconfig`.
+
+**Attack/risk mitigated:** Accidental commits as `root@localhost` or `builduser@ci-runner-7` that pollute history with unattributable authorship. Common on fresh VMs, containers, and CI environments.
+
+**What could break:** Commits will fail if you haven't run `git config user.name` and `git config user.email`. This is intentional friction — the first commit on a new machine requires explicit identity setup.
+
+**Why this default:** The cost of one extra setup step is negligible. The cost of unattributable commits in a regulated codebase is an audit finding.
+
+---
+
+## Object Integrity
+
+### `transfer.fsckObjects = true` / `fetch.fsckObjects = true` / `receive.fsckObjects = true`
+
+**What it does:** Forces git to validate the structural integrity and hash consistency of every object (blob, tree, commit, tag) during transfer, fetch, and receive operations. Malformed objects are rejected.
+
+**Attack/risk mitigated:** Malicious or corrupted packfiles that exploit parsing vulnerabilities in the git binary. Historical CVEs include integer overflows in packfile handling and crafted objects that trigger code execution. Also catches silent data corruption from disk/network errors.
+
+**What could break:** Adds ~5-10% overhead to clone and fetch operations on large repositories. Some very old repositories with technically malformed (but benign) objects may fail to clone until the upstream runs `git fsck --full` and fixes them.
+
+**Why this default:** The performance cost is small. The alternative — silently accepting corrupted objects — has no upside.
+
+### `transfer.bundleURI = false`
+
+**What it does:** Disables the bundle URI mechanism, which allows git servers to redirect clients to pre-packaged bundle files for faster initial clones.
+
+**Attack/risk mitigated:** Reduces attack surface. Bundle URIs could redirect clients to attacker-controlled servers serving malicious bundles. The feature is relatively new (Git 2.39+) and not widely audited.
+
+**What could break:** Initial clone performance for repositories hosted behind CDN-backed bundle URIs. GitHub does not currently use this feature for public repositories.
+
+**Why this default:** No measurable benefit for most users. The feature's security properties are still maturing.
+
+### `fetch.prune = true`
+
+**What it does:** Automatically removes local remote-tracking references (e.g., `origin/feature-x`) when the corresponding remote branch has been deleted.
+
+**Attack/risk mitigated:** Stale remote refs can be confusing and misleading. In a security context, a deleted branch that still appears locally may cause a developer to base work on abandoned or reverted code.
+
+**What could break:** Nothing. This matches the behavior of `git fetch --prune`. Pruning only affects remote-tracking refs, not local branches.
+
+**Why this default:** Pure hygiene with zero downside.
+
+---
+
+## Protocol Restrictions
+
+### `protocol.version = 2`
+
+**What it does:** Uses Git wire protocol v2 for client-server communication. Protocol v2 is more efficient (the server doesn't advertise all refs upfront) and has a smaller attack surface.
+
+**Attack/risk mitigated:** Protocol v0/v1 sends the full ref advertisement on every connection, which leaks information about all branches and tags. Protocol v2 uses a capability-based negotiation that only transfers requested data.
+
+**What could break:** Nothing in practice. Protocol v2 has been supported since Git 2.26 (April 2020) and all major hosting platforms support it. The client falls back gracefully if the server doesn't support v2.
+
+**Why this default:** Strictly better. No known compatibility issues with any major git host.
+
+### `protocol.allow = never` (default-deny)
+
+### `protocol.https.allow = always` / `protocol.ssh.allow = always`
+
+### `protocol.file.allow = user` / `protocol.git.allow = never` / `protocol.ext.allow = never`
+
+**What it does:** Implements a default-deny protocol policy. Only HTTPS and SSH are permitted. The `file://` protocol is restricted to user-initiated operations. The unencrypted `git://` protocol and the `ext://` external transport helper are blocked entirely.
+
+**Attack/risk mitigated:**
+- `git://` transmits data unencrypted and unauthenticated — trivial MITM.
+- `ext://` allows arbitrary command execution via transport helpers — this is by design, not a bug, but it's a dangerous capability that submodule URLs can exploit (e.g., CVE-2023-29007).
+- `file://` is restricted because embedded bare repositories in cloned repos can be used for attacks (CVE-2022-39253).
+
+**What could break:** Repositories that use `git://` URLs for remotes (rare — GitHub deprecated `git://` in 2022). The `url.https://.insteadOf` rewrite handles this automatically for HTTP URLs.
+
+**Why this default:** The blocked protocols have no legitimate use case that can't be served by HTTPS or SSH. The risk/benefit ratio is extreme.
+
+---
+
+## Filesystem Protection
+
+### `core.protectNTFS = true` / `core.protectHFS = true`
+
+**What it does:** Blocks path manipulation attacks that exploit NTFS 8.3 short-name aliases (e.g., `GIT~1` resolving to `.git`) and HFS+ Unicode normalization (e.g., `.git` composed differently). Enabled on all platforms, not just Windows/macOS.
+
+**Attack/risk mitigated:** CVE-2019-1352 (NTFS), various HFS+ attacks. A malicious repository can craft filenames that resolve to `.git/hooks/` on case-insensitive or normalizing filesystems, achieving code execution on clone.
+
+**What could break:** Repositories containing filenames that happen to collide with NTFS 8.3 short names (extremely rare outside deliberate attacks).
+
+**Why this default:** Enabled even on Linux because developers may clone repos onto external drives or share via mixed-OS teams.
+
+### `core.fsmonitor = false`
+
+**What it does:** Disables the filesystem monitor integration (fsmonitor, Watchman). This feature speeds up `git status` in large repos by using OS-level file change notifications.
+
+**Attack/risk mitigated:** The fsmonitor hook (`core.fsmonitor--hook-version`) can execute arbitrary commands. A malicious repository could set this in its local config. Disabling it globally prevents this vector.
+
+**What could break:** Performance of `git status` in very large repositories (100k+ files) where fsmonitor provides significant speedups. Developers working on such repos can override this per-repo.
+
+**Why this default:** Most repositories are not large enough to notice the difference. The attack surface is not worth the performance gain for typical use.
+
+### `core.symlinks = false` (interactive-only, skipped in `-y` mode)
+
+**What it does:** Tells git to not create symbolic links in the working tree. Instead, symlinks are stored as plain text files containing the link target path.
+
+**Attack/risk mitigated:** CVE-2024-32002 — repositories with crafted submodules could trick git into writing files outside the repository via symlink following during clone, achieving remote code execution on Windows and macOS.
+
+**What could break:** Any project that relies on symlinks: Node.js monorepos (`node_modules/.bin/`), shared configuration files, many build systems. This is the most likely setting to cause real workflow breakage.
+
+**Why this default:** **Not applied in `-y` mode** specifically because of breakage risk. In interactive mode, the user is asked with a clear warning. We already mitigate the primary CVE via `submodule.recurse = false`, so this is defense-in-depth, not the only protection.
+
+---
+
+## Hook Control
+
+### `core.hooksPath = ~/.config/git/hooks`
+
+**What it does:** Redirects git hook execution from each repository's `.git/hooks/` directory to a centralized, user-controlled directory.
+
+**Attack/risk mitigated:** Malicious repositories can include hooks (e.g., `pre-commit`, `post-checkout`) that execute on clone, commit, or checkout. By redirecting to a user-managed directory, repo-local hooks are ignored unless explicitly installed.
+
+**What could break:** Project-specific hooks defined in `.git/hooks/` or installed by frameworks like `husky`, `lefthook`, or `pre-commit`. Teams using these must either: (a) install their hooks into the global hooks directory, or (b) override `core.hooksPath` per-repo via `git config --local`.
+
+**Why this default:** The attack is trivial to execute and devastating (arbitrary code execution). Teams that need repo-local hooks can override per-repo.
+
+---
+
+## Pre-commit Hook (gitleaks)
+
+### Gitleaks pre-commit hook installation
+
+**What it does:** Installs a pre-commit hook at `~/.config/git/hooks/pre-commit` that runs `gitleaks protect --staged` before every commit, scanning the staged diff for secrets (API keys, passwords, private keys, etc.).
+
+**Attack/risk mitigated:** Secret leakage — the single most exploited vulnerability class in git. GitGuardian's 2026 report found 29 million new secrets on public GitHub in 2025. Median time-to-discovery by attackers: 20 seconds.
+
+**What could break:** False positives on test fixtures or example credentials may require bypassing with `SKIP_GITLEAKS=1 git commit`. Adds ~1-2 seconds to each commit.
+
+**Why this default:** Both research reports rank pre-commit secret scanning as the #1 workstation-level defense. The hook is safe without gitleaks installed (guards with `command -v`). The `SKIP_GITLEAKS` bypass avoids the need for `--no-verify` which skips ALL hooks.
+
+---
+
+## Repository Safety
+
+### `safe.bareRepository = explicit`
+
+**What it does:** Requires `--git-dir` to be explicitly specified when working with bare repositories. Prevents git from automatically detecting bare repositories in the current directory tree.
+
+**Attack/risk mitigated:** An attacker who can write to a shared filesystem (e.g., `/tmp`, network drives) can plant a bare `.git` directory that git will auto-detect, allowing them to influence git operations of other users in that directory.
+
+**What could break:** Scripts or workflows that `cd` into bare repositories without specifying `--git-dir`. Server-side hooks on self-hosted git servers may need adjustment.
+
+**Why this default:** Bare repository auto-detection in untrusted directories is a documented attack vector. Most developers never interact with bare repos directly.
+
+### `submodule.recurse = false`
+
+**What it does:** Prevents git from automatically initializing and updating submodules during clone, checkout, and pull operations.
+
+**Attack/risk mitigated:** CVE-2024-32002 (clone-time RCE via crafted submodules), CVE-2023-29007 (config injection via overlong submodule URLs), and the general risk of pulling untrusted code automatically. Submodules are the primary vector for filesystem-based git attacks.
+
+**What could break:** Projects using submodules require manual `git submodule update --init`. This is a one-time setup cost per clone.
+
+**Why this default:** Submodule auto-recursion is the enabler for multiple critical CVEs. Explicit initialization is a small price for eliminating an entire attack class.
+
+### `safe.directory = *` detection and removal
+
+**What it does:** Detects and offers to remove the `safe.directory = *` wildcard, which completely disables git's directory ownership safety check.
+
+**Attack/risk mitigated:** CVE-2022-24765 — on shared systems, any user can plant a `.git` directory in a location another user will `cd` into, achieving arbitrary config injection and potentially code execution via hooks.
+
+**What could break:** Removing the wildcard may surface ownership errors for repositories on network drives or external media. These should be added individually: `safe.directory = /path/to/specific/repo`.
+
+**Why this default:** The wildcard is always wrong. It exists because people encounter the ownership error and google a quick fix without understanding what they're disabling.
+
+---
+
+## Pull/Merge Hardening
+
+### `pull.ff = only` / `merge.ff = only`
+
+**What it does:** Refuses non-fast-forward merges and pulls. If the remote branch has diverged, git will error instead of creating a merge commit or silently rebasing.
+
+**Attack/risk mitigated:** Force-pushed branches (rewritten history) are surfaced as errors rather than silently merged. This makes history rewriting attacks visible — the developer must explicitly decide how to handle the divergence.
+
+**What could break:** Workflows that routinely use merge commits will need to switch to `git pull --rebase` or `git merge --no-ff` explicitly. Some teams prefer merge commits for feature branch integration.
+
+**Why this default:** Silent non-fast-forward merges hide potentially dangerous history rewrites. Making divergence explicit is strictly safer. Teams that want merge commits can override per-repo.
+
+---
+
+## Transport Security
+
+### `url."https://".insteadOf = http://`
+
+**What it does:** Automatically rewrites any `http://` remote URL to `https://`, ensuring all HTTP-based git operations use TLS encryption.
+
+**Attack/risk mitigated:** Plaintext HTTP transmits credentials and code in the clear, enabling trivial MITM attacks on any network between the developer and the git server.
+
+**What could break:** Repositories hosted on servers that genuinely only support HTTP (no TLS). This is increasingly rare and is itself a security concern.
+
+**Why this default:** There is no legitimate reason to use unencrypted HTTP for git operations in 2026.
+
+### `http.sslVerify = true`
+
+**What it does:** Enforces TLS certificate verification for all HTTPS git operations. This is git's default, but the script audits it because `http.sslVerify = false` is a common "quick fix" that people forget to undo.
+
+**Attack/risk mitigated:** Disabling SSL verification allows MITM attacks even over HTTPS — the attacker presents any certificate and git accepts it.
+
+**What could break:** Self-signed certificates on internal git servers. The proper fix is to add the CA certificate to git's trust store (`http.sslCAInfo`), not to disable verification globally.
+
+**Why this default:** Ensuring the default hasn't been overridden. This is a safety net, not a new restriction.
+
+---
+
+## Credential Storage
+
+### Platform-specific credential helper (`osxkeychain` / `libsecret`)
+
+**What it does:** Configures git to store credentials in the OS keychain (macOS Keychain, Linux libsecret/GNOME Keyring) instead of plaintext files.
+
+**Attack/risk mitigated:** `git-credential-store` writes passwords to `~/.git-credentials` in plaintext. Modern infostealer malware specifically targets this file. OS keychains encrypt at rest and require authentication to access.
+
+**What could break:** Nothing. Credential helpers are transparent to git operations. The only friction is initial keychain authentication on first use.
+
+**Why this default:** Plaintext credential storage is the #1 workstation-level credential theft vector according to both research reports.
+
+---
+
+## Credential Hygiene (audit-only)
+
+### Plaintext file detection (`~/.git-credentials`, `~/.netrc`, `~/.npmrc`, `~/.pypirc`)
+
+**What it does:** Warns if plaintext credential files exist on the filesystem. Does not modify or delete them.
+
+**Attack/risk mitigated:** These files are primary targets for infostealer malware and are trivially readable by any process running as the user.
+
+**What could break:** Nothing — audit only.
+
+**Why audit-only:** Deleting credential files could lock the user out of services. The script warns and lets the user decide.
+
+---
+
+## Global Gitignore
+
+### `core.excludesFile = ~/.config/git/ignore`
+
+**What it does:** Creates a global gitignore with patterns for common secret files (`.env`, `*.pem`, `*.key`, `credentials.json`), Terraform state (`*.tfstate`), and OS/IDE artifacts.
+
+**Attack/risk mitigated:** Accidental commits of secrets and credentials. No amount of scanning catches what was never tracked in the first place.
+
+**What could break:** Nothing — `.gitignore` only affects untracked files. Files already tracked are unaffected. The `!.env.example` negation allows committing example env files.
+
+**Why this default:** A global gitignore is the simplest possible defense against the most common category of git security incidents.
+
+---
+
+## Defaults
+
+### `init.defaultBranch = main`
+
+**What it does:** Sets the default branch name for new repositories to `main` instead of `master`.
+
+**Attack/risk mitigated:** None directly. This is an industry standardization that reduces confusion and aligns with GitHub's default (changed in October 2020).
+
+**What could break:** Scripts that hardcode `master`. These should be updated regardless.
+
+**Why this default:** Consistency with the ecosystem. Every major git hosting platform now defaults to `main`.
+
+---
+
+## Forensic Readiness
+
+### `gc.reflogExpire = 180.days` / `gc.reflogExpireUnreachable = 90.days`
+
+**What it does:** Extends git's reflog retention from the defaults (90 days reachable / 30 days unreachable) to 180/90 days. The reflog records every HEAD movement — commits, checkouts, resets, rebases.
+
+**Attack/risk mitigated:** In a post-compromise investigation, the reflog is the primary tool for reconstructing what happened. Extended retention gives incident responders more time to discover and investigate force-push attacks, unauthorized commits, and branch manipulation.
+
+**What could break:** Slightly more disk usage from retained reflog entries. The impact is negligible — reflogs are small text records.
+
+**Why this default:** The Claude research report specifically recommends this for forensic readiness. The disk cost is trivial compared to the investigative value.
+
+---
+
+## Visibility
+
+### `log.showSignature = true`
+
+**What it does:** Shows GPG/SSH signature verification status in `git log` output by default.
+
+**Attack/risk mitigated:** Makes unsigned or invalid signatures visible in normal workflow. Without this, developers must remember to use `git log --show-signature` to check.
+
+**What could break:** Log output is slightly more verbose. Some terminal environments may not render the verification status cleanly.
+
+**Why this default:** Signature verification is only useful if people see the results. Making it visible by default closes the gap between "we sign commits" and "we verify signatures."
+
+---
+
+## Signing Configuration
+
+### `gpg.format = ssh`
+
+**What it does:** Uses SSH keys (instead of GPG) for commit and tag signing.
+
+**Attack/risk mitigated:** Same as GPG signing — proves key possession at commit time, preventing commit author impersonation (the PHP git server compromise of 2021 is the canonical example).
+
+**Why SSH over GPG:** SSH keys are already managed by every developer. GPG requires a separate keyring, key server interaction, and has a notoriously steep learning curve. SSH signing (available since Git 2.34) provides equivalent cryptographic guarantees with dramatically less operational friction.
+
+**Trade-off:** GPG has native support for key expiration and revocation. SSH signing on GitHub lacks automatic expiration — a compromised SSH key's signatures remain "Verified" even after the key is removed from the account. For high-security environments, GPG may be preferable despite the friction.
+
+### `commit.gpgsign = true` / `tag.gpgsign = true` / `tag.forceSignAnnotated = true`
+
+**What it does:** Automatically signs all commits and tags with the configured signing key.
+
+**Attack/risk mitigated:** Without signing, anyone who can push to a repository can impersonate any other developer by setting `user.name` and `user.email` to their values. Signed commits prove the private key holder created the commit.
+
+**What could break:** Commits will fail if no signing key is configured. The script only enables these settings when a key is available.
+
+**Why this default:** Commit signing is an accountability control. In the PHP compromise, malicious commits were attributed to Rasmus Lerdorf and Nikita Popov — signing would have immediately flagged them as forgeries.
+
+### `gpg.ssh.allowedSignersFile = ~/.config/git/allowed_signers`
+
+**What it does:** Points git to a local file mapping email addresses to their authorized public keys, enabling local signature verification without a network round-trip.
+
+**What could break:** Nothing — the file is additive. Without it, local verification simply doesn't work (signatures are only verified on the hosting platform).
+
+---
+
+## SSH Configuration
+
+### `StrictHostKeyChecking = accept-new`
+
+**What it does:** Automatically accepts host keys on first connection (TOFU — Trust On First Use) but rejects changed keys on subsequent connections.
+
+**Trade-off:** `ask` (the default) prompts on every new host — most users blindly type "yes" without verifying the fingerprint, providing no real security benefit. `no` accepts anything, including MITM attacks. `accept-new` is the pragmatic middle ground: it stops the prompt fatigue while still detecting host key changes (the actual attack scenario).
+
+### `HashKnownHosts = yes`
+
+**What it does:** Stores host entries in `~/.ssh/known_hosts` as hashed values instead of plaintext hostnames.
+
+**Attack/risk mitigated:** If the known_hosts file is exfiltrated, the attacker cannot enumerate which servers the developer connects to. Hashing makes the file useless for reconnaissance.
+
+**What could break:** Manual inspection of `known_hosts` becomes impossible. `ssh-keygen -F hostname` still works for lookups.
+
+### `IdentitiesOnly = yes`
+
+**What it does:** Only offers SSH keys explicitly configured in `~/.ssh/config` (via `IdentityFile`) or specified on the command line. Without this, ssh-agent offers ALL loaded keys to every server.
+
+**Attack/risk mitigated:** A malicious SSH server can enumerate which keys a client holds by observing which public keys are offered during authentication. With many keys loaded, this leaks information about which services the developer has access to.
+
+**What could break:** Connections that rely on ssh-agent offering the right key automatically will need explicit `IdentityFile` entries in `~/.ssh/config`. This is good practice regardless.
+
+### `AddKeysToAgent = yes`
+
+**What it does:** Automatically adds keys to the SSH agent after first use, so the passphrase is only entered once per session.
+
+**Why this default:** Reduces friction for passphrase-protected keys. Without this, developers either skip passphrases entirely (worse security) or get frustrated re-entering them (leads to workarounds).
+
+### `PubkeyAcceptedAlgorithms = ssh-ed25519,sk-ssh-ed25519@openssh.com,...`
+
+**What it does:** Restricts which public key algorithms the SSH client will offer and accept. Limited to ed25519, ed25519-sk (FIDO2), and ECDSA NIST P-256 variants (including sk).
+
+**Attack/risk mitigated:** Prevents negotiation down to weak algorithms (DSA, RSA with SHA-1). Forces modern cryptography.
+
+**What could break:** Connections to legacy servers that only support RSA. These servers should be upgraded; RSA-SHA1 is deprecated by OpenSSH since version 8.7.
+
+**Why these algorithms:** Ed25519 is the recommended default (fast, small keys, no parameter pitfalls). ECDSA P-256 is included because some FIDO2 hardware keys only support it. RSA is excluded because accepting it creates a fallback path to weaker cryptography.
+
+---
+
+## SSH Key Hygiene (audit-only)
+
+### Weak key detection (DSA, ECDSA, short RSA)
+
+**What it does:** Scans `~/.ssh/*.pub` and keys referenced in `~/.ssh/config` for deprecated or weak key types.
+
+**Why audit-only:** Key migration requires generating new keys, updating authorized_keys on all servers, and reconfiguring services. This is too impactful to automate.
+
+---
+
+## Admin Recommendations (informational only)
+
+These settings require server/org-level access and cannot be applied by a workstation tool:
+
+- **Branch protection rules** — prevent direct pushes to main
+- **Vigilant mode** — flag unsigned commits visibly on the hosting platform
+- **Force-push restrictions** — prevent history rewriting on protected branches
+- **Fine-grained, short-lived tokens** — reduce blast radius of token compromise
+- **Signed commit requirements** — enforce signing at the server level
+- **Separate signing keys per org** — prevent cross-platform identity correlation (OSINT)

docs/research/Claude Opus 4.6 report.md

@@ -0,0 +1,483 @@
+# Git Security Hardening: A Practitioner's Reference
+
+**The single most impactful thing an organization can do to harden its git security posture is enable push-time secret scanning.** GitGuardian's 2026 State of Secrets Sprawl report found **29 million new hardcoded secrets** on public GitHub in 2025 alone — a 34% year-over-year increase — with 64% of secrets from 2022 still unrevoked. Secret exposure remains the highest-likelihood, highest-impact attack surface because it requires zero sophistication to exploit: attackers scan public commits in real time, with a median time-to-discovery of **20 seconds** (Meli et al., NDSS 2019). Combined with branch protection enforcement, commit signing, and least-privilege token management, organizations can eliminate the most common git-related breach vectors with moderate effort.
+
+This report covers the full git attack surface — from developer workstations through hosted platforms to CI/CD integration points — with platform-specific guidance for GitHub, GitLab, and Azure DevOps. Each section includes a threat model, numbered hardening checklist, real-world incident motivation, and residual risk assessment.
+
+---
+
+## Executive summary: ten highest-impact hardening measures
+
+Ranked by risk reduction per unit of implementation effort for a typical 10–50 developer organization:
+
+1. **Enable push-time secret scanning** (GitHub Secret Protection or GitLab Ultimate push protection). Blocks the most frequently exploited vulnerability class before it enters the repository. ~1 hour to enable org-wide.
+2. **Require pull request reviews on default and release branches** with dismissal of stale approvals. Prevents direct pushes of malicious or vulnerable code. ~30 minutes per repository, automatable via rulesets.
+3. **Replace classic PATs with fine-grained, short-lived tokens** (GitHub fine-grained PATs, GitLab project tokens, or GitHub Apps). Eliminates the "keys to the kingdom" single-token failure mode that enabled the tj-actions and Trivy compromises. ~1 day for audit and migration.
+4. **Enforce 2FA/MFA for all organization members.** Prevents account takeover — the root cause of the Gentoo GitHub compromise. ~1 hour to enable; budget 2 weeks for member compliance.
+5. **Install a pre-commit hook stack** (gitleaks + framework) on all developer machines. Catches secrets before they enter git history, where removal is costly. ~2 hours via `core.hooksPath`.
+6. **Pin GitHub Actions to full commit SHAs**, not version tags. Prevents supply-chain injection via mutable tags, as exploited in the tj-actions/changed-files and Trivy incidents. ~1 day for audit and update.
+7. **Enable SSH commit signing with ed25519 keys.** Prevents commit author impersonation — the attack vector in the PHP git server compromise. ~1 hour per developer.
+8. **Deploy a hardened `.gitconfig` template** org-wide (`fsckObjects`, `safe.bareRepository = explicit`, protocol restrictions). Blocks multiple client-side attack classes including CVE-2024-32002. ~30 minutes.
+9. **Stream audit logs to a SIEM** (or at minimum, enable and review them weekly). Provides detection of privilege escalation, branch protection tampering, and anomalous clone activity. ~4 hours for initial setup.
+10. **Restrict AI coding agent permissions** — enforce least-privilege tokens, prevent `--no-verify` bypasses, and require PR review for all AI-generated commits. Addresses the fastest-growing secret exposure vector (AI-assisted commits leak secrets at **2× the baseline rate**).
+
+For organizations that can implement only five changes this quarter, start with items 1, 2, 3, 4, and 5.
+
+---
+
+## Table of contents
+
+1. [Secret exposure](#1-secret-exposure)
+2. [Authentication and access control](#2-authentication-and-access-control)
+3. [Commit integrity](#3-commit-integrity)
+4. [Branch protection and code review enforcement](#4-branch-protection-and-code-review-enforcement)
+5. [Supply chain attacks via git](#5-supply-chain-attacks-via-git)
+6. [Git hosting platform hardening](#6-git-hosting-platform-hardening)
+7. [Developer workstation git security](#7-developer-workstation-git-security)
+8. [Audit, monitoring, and incident response](#8-audit-monitoring-and-incident-response)
+9. [Platform security feature comparison](#9-github-vs-gitlab-vs-azure-devops-security-feature-comparison)
+10. [Appendix A: Minimal `.gitconfig` hardening template](#appendix-a-minimal-gitconfig-hardening-template)
+11. [Appendix B: Pre-commit hook stack recommendation](#appendix-b-pre-commit-hook-stack-recommendation)
+
+---
+
+## 1. Secret exposure
+
+### Threat model
+
+**Who:** Any attacker scanning public repositories, or an insider with read access to private repos. **What:** Credentials, API keys, private keys, database connection strings committed to git history. **How:** Automated scanning of commits in real time (bots monitor the GitHub Events API), manual inspection after a breach, or scraping of repository history.
+
+The scale of this problem is staggering. The landmark NDSS 2019 study by Meli et al. ("How Bad Can It Git?") found over **100,000 repositories** with leaked secrets, with a median of **1,793 unique new keys appearing per day** across public GitHub. Of these, **89% were genuinely sensitive** — not test keys. GitGuardian's 2026 report shows the problem is accelerating: **29 million new secrets** detected in 2025, and repositories using AI coding assistants exhibit a **6.4% secret leakage rate** versus a 1.5% baseline.
+
+The Uber 2016 breach is the canonical cautionary tale: attackers found **hardcoded AWS access keys** in a private GitHub repository (accessed via credential-stuffed passwords on accounts without MFA). Those keys unlocked an S3 bucket containing 57 million user records. The result: a **$148 million FTC fine** and the criminal conviction of Uber's CISO for concealing the breach.
+
+### Hardening checklist
+
+**1. Enable push-time secret scanning on the hosting platform.** GitHub Secret Protection ($19/committer/month, now available on Team plans) blocks pushes containing detected secret patterns before they enter the repository. GitLab Ultimate provides equivalent push protection via server-side pre-receive hooks. Azure DevOps offers GitHub Advanced Security for Azure DevOps with similar capabilities. Push-time blocking is dramatically more effective than post-commit alerting — GitGuardian data shows **70% of secrets leaked in 2022 remained active** through 2025, indicating that alert-only approaches fail due to slow remediation.
+
+**2. Deploy a pre-commit secret scanning tool** on all developer workstations (see Appendix B for detailed tool selection). This catches secrets before they reach the server, complementing platform-side scanning.
+
+**3. Maintain comprehensive `.gitignore` patterns.** Every repository should exclude `.env`, `*.pem`, `*.key`, `*.p12`, `*.tfstate`, `credentials.json`, `service-account*.json`, `.npmrc`, `.pypirc`, and similar files. Use a global gitignore (`core.excludesfile`) for personal patterns plus repository-level `.gitignore` for project-specific ones.
+
+**4. Understand and address the persistence problem.** Running `git rm secret.key && git commit` does **not** remove the secret from history. Git stores content as immutable blob objects; the original blob persists in packfiles and is cloned by every downstream user. **The primary remediation is always to rotate the secret immediately.** History rewriting is secondary cleanup. Use `git-filter-repo` (recommended by the Git project as the replacement for the deprecated `git filter-branch`) or BFG Repo-Cleaner. After rewriting, run `git reflog expire --expire=now --all && git gc --prune=now --aggressive`, force-push, and contact platform support to purge cached objects. Note that forks retain the pre-rewrite history, and all developers must delete and re-clone.
+
+**5. Configure custom secret patterns** for organization-specific credential formats (internal API keys, database connection strings) beyond the default detection patterns provided by platforms.
+
+### Residual risk
+
+Push-time scanning catches only **known secret patterns**. Generic passwords, custom token formats, and secrets embedded in binary files evade pattern-based detection. The 2026 GitGuardian report notes that **58% of leaked credentials are "generic secrets"** that bypass standard detection. Defense-in-depth (pre-commit hooks + push protection + periodic full-history scans with TruffleHog's active verification) reduces but does not eliminate this residual risk. The operational cost is modest: pre-commit hooks add ~1–3 seconds to each commit, and occasional false positives require developer time to triage.
+
+---
+
+## 2. Authentication and access control
+
+### Threat model
+
+**Who:** External attackers via credential theft, phishing, or token leakage; insiders with excessive permissions. **What:** Unauthorized access to repositories, code modification, secret exfiltration. **How:** Compromised PATs, stolen SSH keys, OAuth token theft, or account takeover via password reuse.
+
+The April 2022 Heroku/Travis CI OAuth token compromise demonstrated the blast radius of over-privileged tokens: stolen OAuth tokens from two integrators provided access to private repositories of dozens of organizations, including GitHub's own npm infrastructure. More recently, the March 2025 tj-actions/changed-files compromise (CVE-2025-30066) stemmed from a single compromised PAT belonging to a bot account — that one token affected **23,000+ downstream repositories**. The March 2026 Trivy supply-chain attack (CVE-2026-28353, CVSS 10.0) traced back to a single org-scoped PAT (`ORG_REPO_TOKEN`) used across 33 workflows; incomplete rotation after the first breach enabled a second, more devastating attack.
+
+### Hardening checklist
+
+**1. Use ed25519 SSH keys exclusively.** Ed25519 provides equivalent security to RSA-4096 with much smaller keys (68 vs. 544 characters), faster operations, and no parameter-selection pitfalls. Generate with `ssh-keygen -t ed25519 -C "user@company.com"`. GitHub blocks legacy RSA/SHA-1 signatures. For maximum security, use FIDO2 hardware-backed keys: `ssh-keygen -t ed25519-sk -O resident -O verify-required`.
+
+**2. Replace classic PATs with fine-grained, scoped tokens.** GitHub classic PATs (`ghp_` prefix) with `repo` scope grant read/write access to **every repository the user can access** — a textbook violation of least privilege. GitHub fine-grained PATs (`github_pat_` prefix) scope to specific repositories with granular permissions and mandatory expiration. GitLab project/group access tokens provide similar scoping. Set maximum PAT lifetimes via org policy: 90 days for CI/CD, 30 days for one-off tasks.
+
+**3. Prefer GitHub Apps over PATs for automation.** GitHub Apps generate **short-lived installation tokens** (1-hour expiry) with fine-grained, repository-scoped permissions — not tied to any human account. They survive employee departures without credential rotation and provide auditable "on behalf of" action trails. This is the single most effective control against the "over-privileged bot token" failure mode.
+
+**4. Enforce SAML SSO and audit legacy credentials.** On GitHub Enterprise Cloud, PATs and SSH keys must be separately authorized for SSO after creation. Critical gap: on GitLab, project/group access tokens and deploy keys **bypass SSO enforcement entirely**. On Azure DevOps, PATs bypass device compliance and MFA requirements — only IP-fencing policies apply to non-interactive flows.
+
+**5. Deploy SSH Certificate Authorities** (GitHub Enterprise Cloud). Certificates expire automatically (e.g., daily), eliminating key rotation as a manual process. CAs uploaded after March 2024 require certificate expiration dates.
+
+**6. Implement IP allowlisting where feasible** (GitHub Enterprise Cloud, GitLab self-managed, Azure DevOps via Entra Conditional Access). Practical limitation: dynamic IPs for remote workers require VPN routing, and GitHub-hosted Actions runners have dynamic IPs — requiring self-hosted or larger runners with static IPs.
+
+### Residual risk
+
+SSO enforcement does not protect against all token types on all platforms. IP allowlisting is operationally expensive with distributed teams. Hardware security keys (FIDO2) provide the strongest authentication but introduce device-dependency risk. The operational cost of migrating from classic PATs to fine-grained PATs or GitHub Apps is moderate — budget 1–2 days for audit and migration per team.
+
+---
+
+## 3. Commit integrity
+
+### Threat model
+
+**Who:** Attackers with push access (via compromised credentials or server compromise) impersonating trusted developers. **What:** Forged commits attributed to maintainers, containing backdoors or malicious changes. **How:** Git allows arbitrary `user.name` and `user.email` configuration — without signing, anyone can commit as anyone.
+
+The March 2021 PHP git server compromise is the definitive case study. Attackers pushed two commits to the official `php-src` repository on the self-hosted `git.php.net` server: one attributed to PHP creator Rasmus Lerdorf, another to core maintainer Nikita Popov. Both inserted a backdoor that would execute arbitrary PHP code via a specially crafted HTTP header. The commits had `Signed-off-by` trailers — but those are plain text, not cryptographic signatures. The PHP project subsequently migrated to GitHub and mandated 2FA.
+
+### Hardening checklist
+
+**1. Enable SSH commit signing org-wide** (recommended over GPG for simplicity). SSH signing, available since Git 2.34, uses keys developers already manage — no GPG keyring overhead. Configuration:
+
+```
+git config --global gpg.format ssh
+git config --global user.signingkey ~/.ssh/id_ed25519.pub
+git config --global commit.gpgsign true
+git config --global tag.gpgsign true
+```
+
+Maintain an `allowed_signers` file for local verification: `git config --global gpg.ssh.allowedSignersFile ~/.config/git/allowed_signers`.
+
+**2. Enable GitHub Vigilant Mode** (Settings → SSH and GPG keys → "Flag unsigned commits as unverified"). Without this, unsigned commits show no badge at all — making unsigned and forged commits visually indistinguishable from legitimate ones.
+
+**3. Require signed commits via branch protection** on all default and release branches. GitHub supports this in both classic branch protection and rulesets. GitLab supports it via push rules. **Azure DevOps has no native commit signing verification** — signed commits are accepted but not validated or badged. Third-party pipeline decorators exist but are not equivalent.
+
+**4. Understand what signing does and does not guarantee.** Signing proves **key possession at commit time** — it defeats impersonation and detects tampering. It does **not** prove the legitimate key owner was at the keyboard (a compromised machine with access to `ssh-agent` can produce valid signatures), and it does not prevent intentional malicious commits by a valid signer. Signing is an accountability control, not an authorization control.
+
+**5. Monitor the SHA-1 to SHA-256 transition.** Git has used hardened SHA-1 (the `sha1collisiondetection` library) since Git 2.13.0, which detects known collision attack patterns with negligible false positive rates (< 2⁻⁹⁰). The SHA-1 chosen-prefix collision cost has fallen to approximately **$45,000** (Leurent & Peyrin, USENIX Security 2020, "SHA-1 is a Shambles"), and continues to decline with GPU advances. Git 3.0 (targeted for late 2026) will default new repositories to SHA-256, but **GitHub does not yet support SHA-256 repositories**, creating an ecosystem blocker. Practical risk today: low for most organizations due to the hardened SHA-1, but plan for migration.
+
+### Residual risk
+
+GitHub's squash-and-merge and rebase-and-merge operations create new unsigned commits, breaking signing chains. Sigstore/Gitsign offers keyless signing via OIDC identity, eliminating key management entirely, but GitHub does not yet display "Verified" badges for Gitsign signatures. For signing release artifacts (tarballs, binaries), signify or minisign are lightweight alternatives to GPG.
+
+---
+
+## 4. Branch protection and code review enforcement
+
+### Threat model
+
+**Who:** Malicious insiders, compromised accounts, or external attackers with any write access. **What:** Direct pushes of malicious code to production branches bypassing review. **How:** Pushing directly to unprotected branches, self-approving PRs, exploiting bypass vectors in branch protection configuration.
+
+### Hardening checklist
+
+**1. Require pull requests with at minimum one approving review** on default and release branches across all repositories. Use GitHub rulesets (preferred over classic branch protection — they aggregate restrictively, apply across fork networks, and support org-wide governance) or GitLab protected branches with "Allowed to push: No one."
+
+**2. Enable "Dismiss stale approvals when new commits are pushed"** on all platforms. Without this, a developer can get approval, then push additional malicious commits and merge without re-review.
+
+**3. Enable "Require approval of the most recent reviewable push"** (GitHub) or equivalent. This prevents a reviewer from pushing commits to a PR branch and then approving their own additions — a documented bypass vector identified by Legit Security that GitHub considers "working as expected."
+
+**4. Check "Do not allow bypassing the above settings"** (GitHub) or restrict unprotect permissions (GitLab). By default, GitHub repository admins can bypass all branch protections. This single checkbox is the difference between "branch protection exists" and "branch protection is enforced."
+
+**5. Use CODEOWNERS for security-critical paths** (authentication modules, cryptography, CI/CD configurations, the CODEOWNERS file itself). Protect the CODEOWNERS file with a self-referencing entry: `/.github/CODEOWNERS @security-team`. Validate that all listed code owners are active members with write permissions — invalid or departed users cause CODEOWNERS enforcement to fail silently.
+
+**6. Require status checks before merging** (CI tests, SAST scans, secret scanning). Block merge unless all checks pass and branches are up to date with the target.
+
+**7. Restrict force-push and branch deletion** on protected branches (default on GitHub and GitLab for protected branches, but verify explicitly).
+
+### The "rubber stamp" problem
+
+Branch protection is only as strong as the review process behind it. Research by Edmundson et al. (2013) found that **none of 30 developers** reviewing a web application found all seven known vulnerabilities, and more experience did not correlate with better detection. A 2024 study of OpenSSL and PHP code reviews found that even when security concerns were raised, **18–20% went unfixed** due to disagreements. Code review becomes security theater when PRs are approved in under two minutes without comments, when reviewers lack security training, or when PR sizes exceed 400 lines.
+
+Minimum viable security review: keep PRs under 400 lines, run automated SAST and secret scanning before human review, require conversation resolution before merge, and designate security-trained reviewers as CODEOWNERS for sensitive paths.
+
+### Bypass vectors to monitor
+
+Admin override (without "Do not allow bypassing"), GitHub Actions self-approval (a bot can use `GITHUB_TOKEN` to approve PRs — disable via org settings), PAT-based PR creation and approval (if a `repo`-scoped PAT exists in Actions secrets), and CODEOWNERS misconfiguration (invalid users, unprotected CODEOWNERS file, or the "Require review from Code Owners" toggle not enabled).
+
+---
+
+## 5. Supply chain attacks via git
+
+### Threat model
+
+**Who:** Nation-state actors (xz-utils pattern), opportunistic attackers (pwn requests), or automated bots. **What:** Injecting malicious code into software supply chains via git-hosted repositories, build systems, or CI/CD pipelines. **How:** Social engineering of maintainers, exploitation of CI workflow misconfigurations, fork-based object injection, or dependency confusion.
+
+The **xz-utils backdoor** (CVE-2024-3094, CVSS 10.0) represents the most sophisticated git-related supply chain attack to date. An attacker using the identity "Jia Tan" spent **over two years** building trust in the xz-utils project through legitimate contributions, while sockpuppet accounts ("Jigar Kumar," "Dennis Ens") pressured the burned-out sole maintainer to grant commit access. The backdoor was injected via the build system (M4 macros in the release tarball, not visible in the git source), targeting SSH on Debian/Fedora x86_64 systems. Discovery was accidental: Microsoft engineer Andres Freund noticed SSH logins consuming 500ms instead of 100ms.
+
+The **Codecov breach** (January–April 2021) demonstrated a different vector: attackers extracted a GCS credential from a Docker image layer, modified the Codecov bash uploader script to exfiltrate CI environment variables (including git credentials and tokens) from approximately **29,000 enterprise customers'** CI runners. A customer discovered the compromise by comparing the downloaded script's SHA-256 hash against the one on GitHub — they did not match.
+
+### Hardening checklist
+
+**1. Pin all GitHub Actions to full commit SHAs**, not version tags. Mutable tags are the primary attack vector in Actions supply-chain compromises: the tj-actions/changed-files attacker retroactively updated multiple version tags to reference malicious commits. Use `uses: actions/checkout@b4ffde65f46336ab88eb53be808477a3936bae11` instead of `uses: actions/checkout@v4`.
+
+**2. Set `GITHUB_TOKEN` permissions to read-only by default** at the organization level (Settings → Actions → General → Workflow permissions → Read repository contents and packages permissions). Grant write permissions explicitly per-workflow using the `permissions:` block.
+
+**3. Never use `pull_request_target` with checkout of the PR head.** The `pull_request_target` trigger runs with full repository secrets and write tokens but can be tricked into executing attacker-controlled code from a fork PR. If `pull_request_target` is required, gate execution behind a maintainer-applied label (e.g., `safe-to-test`) and never check out `github.event.pull_request.head.sha`. The February 2026 "hackerbot-claw" campaign exploited exactly this misconfiguration to steal org-scoped PATs from the Trivy project.
+
+**4. Restrict fork creation for sensitive repositories** and audit the fork network. GitHub forks share the underlying object store — data from deleted forks or private forks can remain accessible via commit SHA in the parent repository. This is documented behavior, not a bug. Run `trufflehog github-experimental --repo <URL> --object-discovery` to scan for cross-fork object reference (CFOR) exposures.
+
+**5. Implement SLSA Level 2+ build provenance.** Use the `slsa-framework/slsa-github-generator` reusable workflow to generate signed provenance attestations for release artifacts. Verify with `slsa-verifier` or `gh attestation verify` in deployment pipelines. SLSA L3 (hardened, isolated builds) would have made the SolarWinds attack — where malware was injected at compile time by the SUNSPOT implant, not in the source repository — significantly harder.
+
+**6. Run OpenSSF Scorecard** weekly on all repositories. The automated tool evaluates branch protection, dangerous workflow patterns (including `pull_request_target` misconfigurations), pinned dependencies, token permissions, and signed releases. Integrate via the `ossf/scorecard-action` GitHub Action.
+
+**7. Review `.gitmodules` changes as high-risk in code review.** Submodule URL manipulation (including CVE-2023-29007, which allowed arbitrary git config injection via overlong submodule URLs) is an active attack vector. Prefer proper package managers over submodules where possible.
+
+### Residual risk
+
+The xz-utils pattern — years of social engineering culminating in build-system-only backdoors invisible in git source — is extremely difficult to defend against programmatically. Reproducible builds, multi-maintainer release signing, and comparing source against release tarballs are the best mitigations, but they require significant process maturity. The SLSA framework provides a graduated path toward build integrity.
+
+---
+
+## 6. Git hosting platform hardening
+
+### Threat model
+
+**Who:** External attackers targeting organization-wide misconfigurations; insiders exploiting overly permissive defaults. **What:** Mass data exfiltration, privilege escalation, or persistence via platform settings. **How:** Account takeover of admins (Gentoo pattern), exploitation of default-permissive organization settings, or abuse of integration permissions.
+
+### Hardening checklist
+
+**1. Enforce 2FA for all organization members.** Available on all GitHub tiers (Free, Team, Enterprise). The Gentoo GitHub compromise (June 2018) was enabled by a single admin account without 2FA — the attacker guessed the password using a predictable password scheme. Non-compliant members are removed (GitHub) or blocked (GitLab). Budget a 2-week compliance window.
+
+**2. Set base member permissions to "No permission" or "Read"** rather than the default "Write." Grant additional permissions via teams.
+
+**3. Restrict repository creation to organization owners** or specific teams. Prevent uncontrolled proliferation of repositories with inconsistent security settings.
+
+**4. Disable forking of private repositories** unless specifically required. All forks of public repos are always public — this cannot be overridden.
+
+**5. Set default repository visibility to "Private"** (or "Internal" on Enterprise) to prevent accidental public exposure.
+
+**6. Enable audit log streaming to a SIEM** (see Section 8). GitHub Enterprise streams to Splunk, Datadog, Azure Sentinel, S3, and GCS. GitLab Ultimate streams to HTTP endpoints, S3, GCS, and Azure Event Hubs.
+
+**7. Apply CIS Benchmarks** where available. The CIS GitHub Benchmark (v1.2.0) and CIS GitLab Benchmark (v1.0.1, with 125+ recommendations) provide audit-ready configuration checklists. GitLab provides an open-source CIS benchmark scanner CLI tool. No standalone CIS benchmark exists for Azure DevOps.
+
+### Self-hosted versus cloud
+
+Self-hosting (GitHub Enterprise Server, GitLab self-managed) provides network isolation and data sovereignty but **shifts the patching burden** to the organization. Recent GitLab self-managed CVEs underscore this risk: CVE-2025-25291/25292 (CVSS 8.8, SAML authentication bypass), CVE-2025-6948 (CVSS 8.7, CI/CD pipeline authorization bypass), and CVE-2025-0605 (2FA bypass via Git CLI). For organizations without dedicated security infrastructure teams — the typical Three Backticks Security client — **cloud-hosted platforms are usually more secure** because the vendor handles patching, and the latest security features ship immediately.
+
+---
+
+## 7. Developer workstation git security
+
+### Threat model
+
+**Who:** Attackers who can influence repository content (malicious hooks, crafted objects) or access developer machines. **What:** Code execution on developer machines via cloned repositories, credential theft from insecure storage. **How:** Malicious git hooks, crafted git objects exploiting parsing vulnerabilities, symlink attacks, or plaintext credential files.
+
+**CVE-2024-32002** (Critical) demonstrated this risk: repositories with submodules could trick Git into executing a hook during clone, achieving remote code execution on Windows and macOS. The `git clone` command — seemingly safe — became an attack vector.
+
+### Hardening checklist
+
+**1. Use a secure credential helper.** Never use `git-credential-store` (stores credentials as plaintext in `~/.git-credentials`). Per-platform recommendations: **Windows:** Git Credential Manager (bundled with Git for Windows). **macOS:** `osxkeychain` or GCM. **Linux:** `libsecret` or GCM. For CI/CD, use environment variables or short-lived tokens.
+
+**2. Deploy the hardened `.gitconfig` template** from Appendix A org-wide. Critical directives: `transfer.fsckObjects = true` (verifies integrity of all transferred objects, catching malformed or crafted objects), `safe.bareRepository = explicit` (prevents embedded bare repository attacks), `protocol.git.allow = never` (disables the unencrypted, unauthenticated `git://` protocol), and `core.hooksPath` pointing to a centralized, organization-managed hooks directory.
+
+**3. Never set `safe.directory = *`.** This wildcard **completely disables** the ownership safety check introduced in Git 2.35.2 (CVE-2022-24765), allowing any user on a shared system to exploit a planted `.git` directory. Add specific trusted directories individually.
+
+**4. Set `core.hooksPath` to a centralized, version-controlled hooks directory.** This overrides per-repository `.git/hooks/` directories, preventing execution of untrusted hooks from cloned repos. Distribute standardized hooks (pre-commit secret scanning, commit message validation) via this path.
+
+**5. Enable path traversal protections**: `core.protectNTFS = true` and `core.protectHFS = true` even on Linux servers, to protect developers on mixed-OS teams from NTFS 8.3 short-name attacks (CVE-2019-1352) and HFS+ Unicode normalization attacks.
+
+### AI coding agents require specific controls
+
+AI coding agents are now a material attack surface. Claude Code alone accounts for **over 4% of all public GitHub commits** as of March 2026. GitGuardian reports AI-assisted commits leak secrets at **double the baseline rate** (~3.2% vs. ~1.5%). Key risks and mitigations:
+
+- **Agents bypass pre-commit hooks.** Cursor and Cline are documented to append `--no-verify` to git commits. Mitigation: enforce secret scanning server-side (push protection), not just client-side hooks. Consider the `block-no-verify` package or Claude Code's `PreToolUse` hooks.
+- **Agents with overprivileged tokens.** AI agents given broad PATs can be exploited via prompt injection in repository content (issues, README files, code comments, `.cursorrules` files). The IDEsaster research (December 2025) found **100% of tested AI coding tools** vulnerable to prompt injection, with CVE-2025-53773 (CVSS 9.6) affecting GitHub Copilot. Mitigation: scope agent tokens to read-only on specific repositories; use ephemeral, OAuth-scoped credentials.
+- **Agents performing destructive operations.** Reports document Cursor running `git push --force-with-lease --no-verify` without permission. Mitigation: use Claude Code's auto mode (which blocks force-pushes via a classifier) or restrict agent git permissions to exclude force-push.
+- **62% of AI-generated C programs contain vulnerabilities** (FormAI-v2 dataset, 2024). Treat all AI-generated code as untrusted — enforce the same review requirements as human-authored code.
+
+---
+
+## 8. Audit, monitoring, and incident response
+
+### Threat model
+
+**Who:** Any attacker who has gained access — detection depends on monitoring coverage. **What:** Detecting and responding to compromised accounts, unauthorized changes, and data exfiltration. **How:** Audit log analysis, anomaly detection, and git forensics.
+
+### Hardening checklist
+
+**1. Enable and stream audit logs.** GitHub Enterprise streams to Splunk, Datadog, Azure Sentinel, S3, and GCS. GitLab Ultimate streams structured JSON to HTTP endpoints, S3, GCS, and Azure Event Hubs. Azure DevOps streams to Log Analytics, Splunk, and Event Grid (90-day default retention; audit streaming must be explicitly enabled — it is off by default).
+
+**2. Monitor these critical events**: branch protection rule changes (`protected_branch.destroy`), force-pushes to default branches, repository visibility changes to public, new deploy key creation, PAT creation followed by mass cloning (correlated detection), admin role self-assignment, webhook creation/modification, and SSO/2FA policy changes.
+
+**3. Extend reflog retention for forensic readiness.** Default retention is 90 days (reachable commits) and 30 days (unreachable). Extend with:
+```
+git config --global gc.reflogExpire 180.days
+git config --global gc.reflogExpireUnreachable 90.days
+```
+
+**4. Know the forensic toolkit for post-compromise investigation.** `git reflog --date=iso` shows every change to HEAD with timestamps. Force-push events appear as "forced-update" in `git reflog show origin/main`. `git fsck --unreachable --no-reflogs` finds truly orphaned commits that may contain evidence. **Disable garbage collection immediately** during an investigation: `git config gc.auto 0`.
+
+**5. Integrate git events into existing SIEM detection rules.** Pre-built integrations exist for Microsoft Sentinel (sentinel4github), Datadog Cloud SIEM (native GitHub rules), Panther (Python detection-as-code), Elastic Security (git hook execution detection on Linux endpoints), and Google SecOps (YARA-L rules for GitHub audit logs).
+
+### Residual risk
+
+Audit logs capture platform events, not all git operations. A sophisticated attacker who clones a repository via an authorized token and exfiltrates code will appear as normal `git.clone` activity. Anomaly detection (e.g., mass cloning of multiple private repositories in a short window) is the primary detection mechanism for data exfiltration, but tuning thresholds to avoid alert fatigue requires operational investment.
+
+---
+
+## 9. GitHub vs GitLab vs Azure DevOps security feature comparison
+
+| Security capability | GitHub | GitLab | Azure DevOps |
+|---|---|---|---|
+| **MFA enforcement** | Org/Enterprise (all tiers); blocks non-compliant members | Instance/Group (all tiers); grace period configurable | Via Entra Conditional Access (not native) |
+| **SSO/SAML** | Enterprise Cloud only | All tiers (self-managed); group-level (SaaS) | Native via Entra ID |
+| **Fine-grained tokens** | Fine-grained PATs + GitHub Apps | Project/Group tokens | Scoped PATs (no repo-level scoping) |
+| **Branch protection** | Rulesets (org-wide) + classic rules | Protected branches + push rules (Premium+) | Branch policies with build validation |
+| **Commit signing verification** | ✅ GPG + SSH + S/MIME badges | ✅ GPG + SSH badges | ❌ No native support |
+| **Secret scanning** | 200+ types; push protection ($19/committer/mo) | Secret detection; push protection (Ultimate) | Via GHAzDO ($19/committer/mo) |
+| **SAST (code scanning)** | CodeQL ($30/committer/mo) | Multiple engines (Ultimate, $99/user/mo) | CodeQL via GHAzDO ($30/committer/mo) |
+| **DAST** | Third-party only | ✅ Native (Ultimate) | Third-party only |
+| **Container scanning** | Third-party only | ✅ Native (Ultimate) | Third-party only |
+| **Fuzz testing** | Third-party only | ✅ Web API fuzzing (Ultimate) | Third-party only |
+| **Dependency scanning** | Dependabot (free for alerts) | Native (Ultimate) | Via GHAzDO |
+| **Compliance frameworks** | Rulesets | ✅ Centralized frameworks (Ultimate) | Branch policies only |
+| **Audit log streaming** | Enterprise only | Ultimate only | Log Analytics, Splunk, Event Grid |
+| **IP allowlisting** | Enterprise Cloud | Self-managed (network level) | Entra Conditional Access |
+| **CIS Benchmark** | ✅ v1.2.0 | ✅ v1.0.1 (with scanner tool) | ❌ None |
+| **Self-hosted option** | Enterprise Server | Self-managed CE/EE | Azure DevOps Server |
+| **Security pricing** | Base $21/user + GHAS $49/committer/mo | Ultimate $99/user/mo (all inclusive) | Free base + GHAzDO $49/committer/mo |
+
+**Key takeaway for Three Backticks Security clients:** GitHub offers the most granular token management (fine-grained PATs, GitHub Apps) and the strongest commit signing ecosystem. GitLab Ultimate provides the broadest native scanner coverage (DAST, container scanning, fuzzing) at a simpler all-inclusive price point. Azure DevOps lags significantly in git-specific security — no commit signing verification, no native MFA enforcement, and limited audit capabilities compared to the other two platforms.
+
+---
+
+## Appendix A: Minimal `.gitconfig` hardening template
+
+```ini
+# ============================================================
+# SECURITY-HARDENED ~/.gitconfig — Three Backticks Security
+# Deploy org-wide via configuration management
+# ============================================================
+
+[user]
+    name = Your Name
+    email = your.email@company.com
+    # Prevent commits without explicit identity
+    useConfigOnly = true
+
+[credential]
+    # OS-native secure storage (never use 'store')
+    # Windows: manager | macOS: osxkeychain | Linux: libsecret
+    helper = osxkeychain
+
+[core]
+    # Centralized hooks — overrides per-repo .git/hooks/
+    hooksPath = ~/.config/git/hooks
+    # Path traversal protections (enable on ALL platforms)
+    protectNTFS = true
+    protectHFS = true
+    # Disable symlinks to prevent symlink-based attacks
+    symlinks = false
+
+[transfer]
+    # Verify integrity of ALL transferred objects
+    fsckObjects = true
+    # Disable bundle URI fetching
+    bundleURI = false
+
+[fetch]
+    fsckObjects = true
+    prune = true
+
+[receive]
+    fsckObjects = true
+
+[protocol]
+    version = 2
+
+[protocol "file"]
+    # Restrict local file protocol (CVE-2022-39253)
+    allow = user
+
+[protocol "git"]
+    # DISABLE unencrypted, unauthenticated git:// protocol
+    allow = never
+
+[protocol "ext"]
+    # Disable external transport helpers
+    allow = never
+
+[safe]
+    # Require explicit --git-dir for bare repos
+    bareRepository = explicit
+    # NEVER add: directory = *
+
+[commit]
+    gpgsign = true
+
+[tag]
+    gpgsign = true
+
+[gpg]
+    # SSH signing (simpler than GPG)
+    format = ssh
+
+[gpg "ssh"]
+    allowedSignersFile = ~/.config/git/allowed_signers
+
+[push]
+    default = current
+    autoSetupRemote = true
+
+[init]
+    templateDir = ~/.config/git/template
+    defaultBranch = main
+
+[url "https://"]
+    # Force HTTPS for any git:// URLs
+    insteadOf = git://
+```
+
+---
+
+## Appendix B: Pre-commit hook stack recommendation
+
+### Recommended stack: gitleaks via the pre-commit framework
+
+**Why gitleaks over alternatives:** Gitleaks (Go, MIT license, 160+ built-in detectors) is the best general-purpose pre-commit secret scanner for most organizations. It strikes the optimal balance: fast execution (Go binary, no runtime dependencies), low false-positive rate, extensible TOML configuration, and active maintenance. TruffleHog v3 is more comprehensive (800+ detectors, active API verification) but its AGPL license and heavier runtime make it better suited for CI pipeline scanning than developer-workstation pre-commit hooks. detect-secrets (Yelp) excels in legacy codebases with its baseline approach but requires Python. git-secrets (AWS Labs) is AWS-focused and showing reduced maintenance (272+ unresolved issues).
+
+### Installation via pre-commit framework
+
+```yaml
+# .pre-commit-config.yaml
+repos:
+  - repo: https://github.com/gitleaks/gitleaks
+    rev: v8.21.2
+    hooks:
+      - id: gitleaks
+```
+
+```bash
+# Install pre-commit framework
+pip install pre-commit
+# Install hooks in the repository
+pre-commit install
+# Run against all files (first-time scan)
+pre-commit run --all-files
+```
+
+### Organization-wide deployment via `core.hooksPath`
+
+For enforcement beyond individual repositories:
+
+```bash
+# Create centralized hooks directory
+mkdir -p ~/.config/git/hooks
+
+# Create pre-commit hook that runs gitleaks
+cat > ~/.config/git/hooks/pre-commit << 'EOF'
+#!/bin/bash
+# Org-wide pre-commit secret scanning
+if command -v gitleaks &> /dev/null; then
+    gitleaks protect --staged --redact --verbose
+    if [ $? -ne 0 ]; then
+        echo "❌ Secret detected. Commit blocked."
+        echo "If false positive, use: SKIP=gitleaks git commit"
+        exit 1
+    fi
+fi
+EOF
+chmod +x ~/.config/git/hooks/pre-commit
+
+# Set globally
+git config --global core.hooksPath ~/.config/git/hooks
+```
+
+### Complementary CI pipeline scanning
+
+Add TruffleHog in CI for deeper scanning with active verification:
+
+```yaml
+# GitHub Actions
+- name: TruffleHog scan
+  uses: trufflesecurity/trufflehog@main
+  with:
+    extra_args: --only-verified --results=verified,unknown
+```
+
+### Tool selection matrix
+
+| Criterion | gitleaks | TruffleHog v3 | detect-secrets | git-secrets |
+|---|---|---|---|---|
+| **Best role** | Pre-commit hook | CI pipeline scan | Legacy codebase onboarding | AWS-only environments |
+| **Speed** | Fast (Go binary) | Moderate (verification adds latency) | Fast (diff-only) | Fast (bash/grep) |
+| **False positive rate** | Low | Very low (verification) | Low (baseline filtering) | Moderate |
+| **Maintenance status** | Active | Active | Active | Low maintenance |
+| **License** | MIT | AGPL 3.0 | Apache 2.0 | Apache 2.0 |
+| **Operational cost** | ~1–2s per commit | ~10–30s per scan | ~1s per commit | ~1s per commit |
+
+The recommended stack for a Three Backticks Security client is: **gitleaks as pre-commit hook** (developer workstation) + **TruffleHog v3 in CI** (verified scanning) + **platform push protection** (server-side enforcement). This three-layer approach provides defense-in-depth against the most common and damaging class of git security vulnerabilities.
+
+---
+
+*Prepared by Three Backticks Security. This document reflects the state of git security tooling and platform features as of March 2026. Platform features, pricing, and tool versions should be verified against current vendor documentation before implementation.*

docs/specs/2026-03-31-v0.2.0-expanded-hardening.md

@@ -0,0 +1,330 @@
+# git-harden.sh v0.2.0 — Expanded Hardening Features
+
+## Motivation
+
+Gap analysis of two independent research reports (Claude Opus 4.6 and Gemini 3.1 Pro, March 2026) against the v0.1.0 script identified six feature areas where the script falls short of current best-practice recommendations. All additions follow the existing audit+apply pattern and require no new CLI flags.
+
+### Source Reports
+
+- `docs/research/Claude Opus 4.6 report.md`
+- `docs/research/Gemini 3.1 Pro report.md`
+
+## Scope
+
+All changes are additive — no existing behavior changes. The v0.2.0 script will:
+
+1. Install a gitleaks pre-commit hook
+2. Create and configure a global gitignore
+3. Detect plaintext credential files
+4. Audit SSH key hygiene
+5. Add 8 new git config settings
+6. Detect dangerous `safe.directory = *` wildcard
+
+Version bump: `0.1.0` → `0.2.0`.
+
+---
+
+## Feature 1: Pre-commit Hook Installation (gitleaks)
+
+### Background
+
+Both reports rank pre-commit secret scanning as the single most impactful workstation-level defense. The v0.1.0 script sets `core.hooksPath = ~/.config/git/hooks` but installs no hooks, leaving the directory empty.
+
+### Audit Behavior
+
+- Check if `~/.config/git/hooks/pre-commit` exists and is executable.
+- If it exists, check whether it contains a `gitleaks` invocation (grep for `gitleaks`).
+- `[OK]` if pre-commit hook exists and references gitleaks.
+- `[WARN]` if pre-commit hook exists but does NOT reference gitleaks (user-managed hook — don't touch).
+- `[MISS]` if no pre-commit hook exists.
+
+### Apply Behavior
+
+- Check if `gitleaks` is on `$PATH` via `command -v gitleaks`.
+- If gitleaks is found and no pre-commit hook exists:
+  - Create `~/.config/git/hooks/pre-commit` with the following content:
+    ```bash
+    #!/usr/bin/env bash
+    # Installed by git-harden.sh — global pre-commit secret scanning
+    # To bypass for a single commit: SKIP_GITLEAKS=1 git commit
+    set -o errexit
+    set -o nounset
+    set -o pipefail
+
+    if [ "${SKIP_GITLEAKS:-0}" = "1" ]; then
+        exit 0
+    fi
+
+    if command -v gitleaks >/dev/null 2>&1; then
+        gitleaks protect --staged --redact --verbose
+    fi
+    ```
+  - `chmod +x` the hook.
+- If gitleaks is NOT found:
+  - `[WARN]` with install instructions:
+    - macOS: `brew install gitleaks`
+    - Linux: `brew install gitleaks` or download from GitHub releases
+  - Still create the hook script (it guards with `command -v` so it's safe without gitleaks installed). Prompt the user before creating.
+- If a pre-commit hook already exists (any content): warn and skip. Do not overwrite user-managed hooks.
+
+### Bypass Mechanism
+
+The `SKIP_GITLEAKS=1` environment variable allows a single commit to bypass the hook without `--no-verify` (which skips ALL hooks). This is documented in the hook script itself.
+
+### Acceptance Criteria
+
+- `--audit` reports status of pre-commit hook with gitleaks.
+- Apply creates a working hook that blocks commits containing secrets.
+- Existing user hooks are never overwritten.
+- Hook is safe to install even if gitleaks is not yet installed.
+
+---
+
+## Feature 2: Global Gitignore
+
+### Background
+
+Both reports stress maintaining comprehensive `.gitignore` patterns for secrets. No amount of scanning catches what was never tracked in the first place.
+
+### Audit Behavior
+
+- Check if `core.excludesFile` is set in global git config.
+- If not set: `[MISS]`.
+- If set: check whether the referenced file contains key security patterns (`.env`, `*.pem`, `*.key`).
+  - `[OK]` if file exists and contains at least one security pattern.
+  - `[WARN]` if file exists but lacks security patterns: "Global gitignore at <path> lacks secret patterns (.env, *.pem, *.key). Consider adding them."
+
+### Apply Behavior
+
+- If `core.excludesFile` is not set:
+  - Create `~/.config/git/ignore` with the following patterns:
+    ```gitignore
+    # === Security: secrets & credentials ===
+    .env
+    .env.*
+    !.env.example
+    *.pem
+    *.key
+    *.p12
+    *.pfx
+    *.jks
+    credentials.json
+    service-account*.json
+    .git-credentials
+    .netrc
+    .npmrc
+    .pypirc
+
+    # === Security: Terraform state (contains secrets) ===
+    *.tfstate
+    *.tfstate.backup
+
+    # === OS artifacts ===
+    .DS_Store
+    Thumbs.db
+    Desktop.ini
+
+    # === IDE artifacts ===
+    .idea/
+    .vscode/
+    *.swp
+    *.swo
+    *~
+    ```
+  - Set `core.excludesFile = ~/.config/git/ignore` via `apply_git_setting`.
+- If `core.excludesFile` is already set to a different path:
+  - Print `[INFO]` noting the existing path. Do not modify or overwrite.
+  - If the file lacks security patterns, print `[WARN]` with the missing patterns (informational only — no auto-append).
+
+### Acceptance Criteria
+
+- Audit reports whether `core.excludesFile` is configured.
+- Audit checks existing gitignore files for security pattern coverage and warns if missing.
+- Apply creates the file and sets the config only when nothing is configured.
+- Existing configurations are never modified — warnings are informational.
+- The `!.env.example` negation allows committing example env files.
+
+---
+
+## Feature 3: Plaintext Credential File Detection
+
+### Background
+
+Both reports warn that `git-credential-store` writes passwords to `~/.git-credentials` in plaintext. The Gemini report additionally calls out infostealer malware targeting this file. Adjacent credential files (.netrc, .npmrc, .pypirc) pose similar risks.
+
+### Audit Behavior (audit-only, no apply action)
+
+Check for existence and content of these files:
+
+| File | Detection | Severity |
+|------|-----------|----------|
+| `~/.git-credentials` | File exists | `[WARN]` — "Plaintext git credentials. Migrate to credential helper (osxkeychain/libsecret) and delete this file." |
+| `~/.netrc` | File exists | `[WARN]` — "Plaintext network credentials found. May contain git hosting tokens." |
+| `~/.npmrc` | File contains `_authToken=` followed by a non-empty value (regex: `_authToken=.+`) | `[WARN]` — "npm registry token in plaintext. Use `npm config set` with env vars instead." |
+| `~/.pypirc` | File contains `password` | `[WARN]` — "PyPI credentials in plaintext. Use keyring or token-based auth instead." |
+
+### Apply Behavior
+
+None. The script does not delete or modify user credential files. Warnings are informational only.
+
+### Section Placement
+
+New section: "Credential Hygiene" — placed after the existing "Credential Storage" audit.
+
+### Acceptance Criteria
+
+- Each detected file produces a specific, actionable warning.
+- No false positives on files that don't contain credentials (e.g., .npmrc with only registry URL, no token).
+- No files are modified or deleted.
+
+---
+
+## Feature 4: SSH Key Hygiene Audit
+
+### Background
+
+Both reports recommend ed25519 exclusively. The Claude report notes GitHub blocks legacy RSA/SHA-1 signatures. The Gemini report recommends banning DSA and ECDSA.
+
+### Audit Behavior (audit-only, no apply action)
+
+- Scan `~/.ssh/*.pub` files.
+- Additionally, parse `IdentityFile` directives from `~/.ssh/config` (the v0.1.0 script already has this parsing logic in `detect_existing_keys`) and include any referenced `.pub` files not already covered by the glob.
+- For each `.pub` file, read the first field to determine key type.
+- Use `ssh-keygen -l -f <file>` to extract bit length for RSA keys.
+- Report:
+
+| Key Type | Verdict |
+|----------|---------|
+| `ssh-ed25519` | `[OK]` |
+| `sk-ssh-ed25519@openssh.com` | `[OK]` |
+| `ssh-rsa` with >= 2048 bits | `[WARN]` — "RSA key (%d bits). Consider migrating to ed25519." |
+| `ssh-rsa` with < 2048 bits | `[WARN]` — "Weak RSA key (%d bits). Migrate to ed25519 immediately." |
+| `ssh-dss` | `[WARN]` — "DSA key (deprecated). Migrate to ed25519." |
+| `ecdsa-sha2-*` | `[WARN]` — "ECDSA key. Consider migrating to ed25519." |
+| `sk-ecdsa-sha2-*` | `[OK]` — Hardware-backed ECDSA is acceptable. |
+
+### Apply Behavior
+
+None. Key migration is too risky to automate. Warnings are informational.
+
+### Section Placement
+
+New section: "SSH Key Hygiene" — placed after the existing "SSH Configuration" audit.
+
+### Acceptance Criteria
+
+- All `.pub` files in `~/.ssh/` are scanned and classified.
+- RSA bit length is correctly extracted.
+- No false warnings on ed25519 or ed25519-sk keys.
+- No keys are modified or deleted.
+
+---
+
+## Feature 5: Additional Git Config Settings
+
+### Background
+
+Eight new settings recommended by one or both reports that the v0.1.0 script does not audit or apply.
+
+### Settings
+
+| Setting | Value | Rationale | Report Source | Section |
+|---------|-------|-----------|---------------|---------|
+| `user.useConfigOnly` | `true` | Prevent commits without explicit identity — forces user.name/email to be set, blocking accidental commits under system defaults | Claude | New: "Identity" |
+| `gc.reflogExpire` | `180.days` | Extend reflog retention for forensic readiness (default 90 days) | Claude | New: "Forensic Readiness" |
+| `gc.reflogExpireUnreachable` | `90.days` | Extend unreachable reflog retention (default 30 days) | Claude | New: "Forensic Readiness" |
+| `transfer.bundleURI` | `false` | Disable bundle URI fetching — reduces attack surface | Claude | Existing: "Object Integrity" |
+| `protocol.version` | `2` | Wire protocol v2 — better performance, reduced attack surface from reference advertisements | Gemini | Existing: "Protocol Restrictions" |
+| `init.defaultBranch` | `main` | Modern default branch name | Claude | New: "Defaults" |
+| `core.symlinks` | `false` | Prevent symlink-based attacks (relevant to CVE-2024-32002). **Interactive-only**: prompt with default=yes, but skip in `-y` mode (may break symlink-dependent workflows like Node.js monorepos) | Claude | Existing: "Filesystem Protection" |
+| `fetch.prune` | `true` | Auto-prune stale remote-tracking refs on fetch | Claude | Existing: "Object Integrity" |
+
+### Audit & Apply Behavior
+
+Seven of eight follow the existing `audit_git_setting` / `apply_git_setting` pattern. `core.symlinks` is the exception:
+
+- **Audit**: reports current value like all other settings.
+- **Interactive mode**: prompts with default=yes ("Disable symlinks to prevent symlink-based attacks (CVE-2024-32002)? Note: this may break projects that use symlinks, e.g. Node.js monorepos. [Y/n]").
+- **`-y` mode**: skips `core.symlinks` entirely (does not auto-apply). This is because disabling symlinks can silently break real workflows, and `-y` mode should not cause unexpected breakage.
+
+### Acceptance Criteria
+
+- All 8 settings appear in audit output under their respective sections.
+- All 8 settings are applied (with prompt or auto) in apply mode.
+- Existing tests updated to cover new settings.
+
+---
+
+## Feature 6: `safe.directory` Wildcard Detection
+
+### Background
+
+The Claude report explicitly warns: "Never set `safe.directory = *`." This wildcard completely disables the ownership safety check introduced in Git 2.35.2 (CVE-2022-24765), allowing any user on a shared system to exploit a planted `.git` directory.
+
+### Audit Behavior
+
+- Run `git config --global --get-all safe.directory` and check if any value is `*`.
+- `[WARN]` if `*` is found: "safe.directory = * disables ownership checks (CVE-2022-24765). Remove this setting."
+- No output if `*` is not found (this is not a setting we apply — absence of `*` is the correct state).
+
+### Apply Behavior
+
+- If `*` is detected, prompt the user: "Remove dangerous safe.directory = * setting?"
+- If accepted, run `git config --global --unset safe.directory '*'` (note: must handle the case where multiple values exist — use `--unset-all` if needed, but only for the `*` value).
+
+### Section Placement
+
+Added to existing "Repository Safety" section.
+
+### Acceptance Criteria
+
+- Wildcard detected and warned about in audit mode.
+- Apply mode offers to remove it.
+- Non-wildcard `safe.directory` entries are not affected.
+
+---
+
+## Audit Section Order (v0.2.0)
+
+Updated ordering with new sections integrated:
+
+1. Identity (`user.useConfigOnly`)
+2. Object Integrity (existing + `transfer.bundleURI`, `fetch.prune`)
+3. Protocol Restrictions (existing + `protocol.version`)
+4. Filesystem Protection (existing + `core.symlinks`)
+5. Hook Control (existing)
+6. **Pre-commit Hook** (new — gitleaks)
+7. Repository Safety (existing + `safe.directory` wildcard detection)
+8. Pull/Merge Hardening (existing)
+9. Transport Security (existing)
+10. Credential Storage (existing)
+11. **Credential Hygiene** (new — plaintext file detection)
+12. **Global Gitignore** (new)
+13. **Defaults** (new — `init.defaultBranch`)
+14. **Forensic Readiness** (new — reflog retention)
+15. Visibility (existing)
+16. Signing Configuration (existing)
+17. SSH Configuration (existing)
+18. **SSH Key Hygiene** (new)
+
+---
+
+## Non-Goals
+
+- Package manager integration (no `brew install` or `apt install`).
+- Modifying or deleting user files (credential files, SSH keys).
+- Repository-level hardening (branch protection, CODEOWNERS — these remain in admin recommendations).
+- CI/CD pipeline configuration.
+- GPG signing support (the script remains SSH-signing focused).
+
+## Compatibility
+
+Same as v0.1.0: Bash 3.2+, macOS and Linux. No new dependencies. Gitleaks is optional — the hook is safe without it.
+
+## Testing
+
+- Extend existing BATS test suite to cover all new audit checks and apply actions.
+- Add container test cases for gitleaks hook installation (with and without gitleaks present).
+- Test `safe.directory = *` detection and removal.
+- Test credential file detection with mock files.
+- Test SSH key hygiene with various key types.

test/containers/Containerfile.alpine

@@ -0,0 +1,25 @@
+FROM alpine:3.21
+
+RUN apk add --no-cache \
+        bash \
+        git \
+        openssh-client \
+        openssh-keygen \
+        tmux \
+        coreutils \
+        grep \
+        sed
+
+RUN adduser -D -s /bin/bash testuser
+
+COPY git-harden.sh /home/testuser/git-harden.sh
+COPY test/ /home/testuser/test/
+RUN chown -R testuser:testuser /home/testuser
+
+USER testuser
+WORKDIR /home/testuser
+
+RUN git config --global user.name "Test User" \
+    && git config --global user.email "test@example.com"
+
+CMD ["bash", "test/run.sh"]

test/containers/Containerfile.arch

@@ -0,0 +1,22 @@
+FROM archlinux:base
+
+RUN pacman -Syu --noconfirm \
+        bash \
+        git \
+        openssh \
+        tmux \
+    && pacman -Scc --noconfirm
+
+RUN useradd -m -s /bin/bash testuser
+
+COPY git-harden.sh /home/testuser/git-harden.sh
+COPY test/ /home/testuser/test/
+RUN chown -R testuser:testuser /home/testuser
+
+USER testuser
+WORKDIR /home/testuser
+
+RUN git config --global user.name "Test User" \
+    && git config --global user.email "test@example.com"
+
+CMD ["bash", "test/run.sh"]

test/containers/Containerfile.debian

@@ -0,0 +1,22 @@
+FROM debian:trixie
+
+RUN apt-get update && apt-get install -y --no-install-recommends \
+        bash \
+        git \
+        openssh-client \
+        tmux \
+    && rm -rf /var/lib/apt/lists/*
+
+RUN useradd -m -s /bin/bash testuser
+
+COPY git-harden.sh /home/testuser/git-harden.sh
+COPY test/ /home/testuser/test/
+RUN chown -R testuser:testuser /home/testuser
+
+USER testuser
+WORKDIR /home/testuser
+
+RUN git config --global user.name "Test User" \
+    && git config --global user.email "test@example.com"
+
+CMD ["bash", "test/run.sh"]

test/containers/Containerfile.fedora

@@ -0,0 +1,22 @@
+FROM fedora:42
+
+RUN dnf install -y \
+        bash \
+        git \
+        openssh-clients \
+        tmux \
+    && dnf clean all
+
+RUN useradd -m -s /bin/bash testuser
+
+COPY git-harden.sh /home/testuser/git-harden.sh
+COPY test/ /home/testuser/test/
+RUN chown -R testuser:testuser /home/testuser
+
+USER testuser
+WORKDIR /home/testuser
+
+RUN git config --global user.name "Test User" \
+    && git config --global user.email "test@example.com"
+
+CMD ["bash", "test/run.sh"]

test/containers/Containerfile.ubuntu

@@ -0,0 +1,22 @@
+FROM ubuntu:24.04
+
+RUN apt-get update && apt-get install -y --no-install-recommends \
+        bash \
+        git \
+        openssh-client \
+        tmux \
+    && rm -rf /var/lib/apt/lists/*
+
+RUN useradd -m -s /bin/bash testuser
+
+COPY git-harden.sh /home/testuser/git-harden.sh
+COPY test/ /home/testuser/test/
+RUN chown -R testuser:testuser /home/testuser
+
+USER testuser
+WORKDIR /home/testuser
+
+RUN git config --global user.name "Test User" \
+    && git config --global user.email "test@example.com"
+
+CMD ["bash", "test/run.sh"]

test/e2e.sh

@@ -0,0 +1,385 @@
+#!/usr/bin/env bash
+# test/e2e.sh — Run BATS tests inside containers across Linux distros
+# Usage: test/e2e.sh [--runtime docker|podman] [--rebuild] [distro]
+
+set -o errexit
+set -o nounset
+set -o pipefail
+IFS=$'\n\t'
+
+# ------------------------------------------------------------------------------
+# Constants
+# ------------------------------------------------------------------------------
+
+SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd)"
+readonly SCRIPT_DIR
+REPO_ROOT="$(cd "${SCRIPT_DIR}/.." && pwd)"
+readonly REPO_ROOT
+readonly CONTAINER_DIR="${SCRIPT_DIR}/containers"
+readonly IMAGE_PREFIX="git-harden-test"
+
+# Distro matrix
+readonly DISTROS=(ubuntu debian fedora alpine arch)
+
+# Colors (empty if not a terminal)
+if [ -t 2 ]; then
+    readonly C_RED='\033[0;31m'
+    readonly C_GREEN='\033[0;32m'
+    readonly C_YELLOW='\033[0;33m'
+    readonly C_BOLD='\033[1m'
+    readonly C_RESET='\033[0m'
+else
+    readonly C_RED=''
+    readonly C_GREEN=''
+    readonly C_YELLOW=''
+    readonly C_BOLD=''
+    readonly C_RESET=''
+fi
+
+# Mutable state
+RUNTIME=""
+REBUILD=false
+SKIP_HOST=false
+TARGET_DISTRO=""
+
+# Results tracking (temp dir for parallel result files)
+RESULTS_DIR=""
+
+# ------------------------------------------------------------------------------
+# Helpers
+# ------------------------------------------------------------------------------
+
+die() {
+    printf '%bError:%b %s\n' "$C_RED" "$C_RESET" "$1" >&2
+    exit 1
+}
+
+info() {
+    printf '%b[INFO]%b %s\n' "$C_YELLOW" "$C_RESET" "$1" >&2
+}
+
+# ------------------------------------------------------------------------------
+# Argument parsing
+# ------------------------------------------------------------------------------
+
+parse_args() {
+    while [ $# -gt 0 ]; do
+        case "$1" in
+            --runtime)
+                [ $# -ge 2 ] || die "--runtime requires an argument (docker or podman)"
+                RUNTIME="$2"
+                shift 2
+                ;;
+            --rebuild)
+                REBUILD=true
+                shift
+                ;;
+            --skip-host)
+                SKIP_HOST=true
+                shift
+                ;;
+            --help|-h)
+                usage
+                exit 0
+                ;;
+            -*)
+                die "Unknown option: $1"
+                ;;
+            *)
+                TARGET_DISTRO="$1"
+                shift
+                ;;
+        esac
+    done
+}
+
+usage() {
+    cat >&2 <<'EOF'
+Usage: test/e2e.sh [OPTIONS] [DISTRO]
+
+Run BATS tests inside containers across Linux distributions.
+
+Options:
+  --runtime <docker|podman>   Container runtime (auto-detected if omitted)
+  --rebuild                   Force image rebuild ignoring cache
+  --skip-host                 Skip host interactive tests (run containers only)
+  --help, -h                  Show this help
+
+Distros: ubuntu, debian, fedora, alpine, arch
+
+Examples:
+  test/e2e.sh                 # Run all distros
+  test/e2e.sh alpine          # Run Alpine only
+  test/e2e.sh --runtime podman fedora  # Use Podman, Fedora only
+EOF
+}
+
+# ------------------------------------------------------------------------------
+# Runtime detection
+# ------------------------------------------------------------------------------
+
+detect_runtime() {
+    if [ -n "$RUNTIME" ]; then
+        if ! command -v "$RUNTIME" >/dev/null 2>&1; then
+            die "${RUNTIME} is not installed"
+        fi
+        return
+    fi
+
+    local has_docker=false
+    local has_podman=false
+
+    if command -v docker >/dev/null 2>&1; then
+        has_docker=true
+    fi
+    if command -v podman >/dev/null 2>&1; then
+        has_podman=true
+    fi
+
+    if [ "$has_docker" = true ]; then
+        RUNTIME="docker"
+    elif [ "$has_podman" = true ]; then
+        RUNTIME="podman"
+    else
+        die "Neither docker nor podman found. Install one of them:\n  brew install docker\n  brew install podman"
+    fi
+
+    # Verify the daemon is running
+    if ! "$RUNTIME" info >/dev/null 2>&1; then
+        die "${RUNTIME} daemon is not running. Is the ${RUNTIME} service started?"
+    fi
+}
+
+# ------------------------------------------------------------------------------
+# Build & run
+# ------------------------------------------------------------------------------
+
+build_image() {
+    local distro="$1"
+    local containerfile="${CONTAINER_DIR}/Containerfile.${distro}"
+    local image_name="${IMAGE_PREFIX}:${distro}"
+
+    if [ ! -f "$containerfile" ]; then
+        die "Containerfile not found: $containerfile"
+    fi
+
+    local build_args=()
+    if [ "$REBUILD" = true ]; then
+        build_args+=("--no-cache")
+    fi
+
+    info "Building ${image_name}..."
+    if ! "$RUNTIME" build \
+        ${build_args[@]+"${build_args[@]}"} \
+        -f "$containerfile" \
+        -t "$image_name" \
+        "$REPO_ROOT" 2>&1; then
+        return 1
+    fi
+}
+
+run_tests() {
+    local distro="$1"
+    local image_name="${IMAGE_PREFIX}:${distro}"
+
+    info "Running BATS tests on ${distro}..."
+    if ! "$RUNTIME" run \
+        --rm \
+        --network=none \
+        "$image_name" \
+        bash test/run.sh 2>&1; then
+        return 1
+    fi
+}
+
+run_interactive_tests() {
+    local distro="$1"
+    local image_name="${IMAGE_PREFIX}:${distro}"
+
+    info "Running interactive tests on ${distro}..."
+    if ! "$RUNTIME" run \
+        --rm \
+        --network=none \
+        "$image_name" \
+        bash test/interactive/run-all.sh 2>&1; then
+        return 1
+    fi
+}
+
+run_host_interactive() {
+    info "Running interactive tests on host ($(uname -s))..."
+    if ! bash "${SCRIPT_DIR}/run-interactive.sh" 2>&1; then
+        return 1
+    fi
+}
+
+# Generic entry that times a named test phase and records results.
+# Output is written to a log file; result is recorded in RESULTS_DIR.
+run_distro_entry() {
+    local distro="$1"
+    shift
+    # Remaining args are the function + args to run
+    local start_time
+    start_time="$(date +%s)"
+
+    local log_file="${RESULTS_DIR}/${distro}.log"
+
+    local status="PASS"
+    if ! "$@" > "$log_file" 2>&1; then
+        status="FAIL"
+    fi
+
+    local end_time
+    end_time="$(date +%s)"
+    local duration=$(( end_time - start_time ))
+
+    # Write result file (read by print_summary)
+    printf '%s %s %ds\n' "$distro" "$status" "$duration" > "${RESULTS_DIR}/${distro}.result"
+
+    # Print inline status
+    if [ "$status" = "PASS" ]; then
+        printf '%b  ✓ %s passed (%ds)%b\n' "$C_GREEN" "$distro" "$duration" "$C_RESET" >&2
+    else
+        printf '%b  ✗ %s FAIL (%ds)%b\n' "$C_RED" "$distro" "$duration" "$C_RESET" >&2
+        # Show last 20 lines of log on failure
+        printf '%b  Log tail:%b\n' "$C_YELLOW" "$C_RESET" >&2
+        tail -20 "$log_file" >&2
+    fi
+}
+
+
+# ------------------------------------------------------------------------------
+# Summary
+# ------------------------------------------------------------------------------
+
+print_summary() {
+    printf '\n%b══ Summary ══%b\n' "$C_BOLD" "$C_RESET" >&2
+    printf '%-12s %-8s %s\n' "DISTRO" "STATUS" "DURATION" >&2
+    printf '%-12s %-8s %s\n' "------" "------" "--------" >&2
+
+    local any_failed=false
+    local result_file
+    for result_file in "${RESULTS_DIR}"/*.result; do
+        [ -f "$result_file" ] || continue
+        local d s t
+        IFS=' ' read -r d s t < "$result_file"
+
+        local color="$C_GREEN"
+        if [ "$s" = "SKIP" ]; then
+            color="$C_YELLOW"
+        elif [ "$s" != "PASS" ]; then
+            color="$C_RED"
+            any_failed=true
+        fi
+        printf '%b%-12s %-8s %s%b\n' "$color" "$d" "$s" "$t" "$C_RESET" >&2
+    done
+
+    if [ "$any_failed" = true ]; then
+        return 1
+    fi
+    return 0
+}
+
+# ------------------------------------------------------------------------------
+# Main
+# ------------------------------------------------------------------------------
+
+main() {
+    parse_args "$@"
+    detect_runtime
+
+    info "Using runtime: ${RUNTIME}"
+
+    # Set up results directory
+    RESULTS_DIR="$(mktemp -d)"
+    trap 'rm -rf "$RESULTS_DIR"' EXIT
+
+    # Run interactive tests on the host first (covers macOS ssh-keygen)
+    if [ "$SKIP_HOST" = true ]; then
+        info "Skipping host interactive tests (--skip-host)"
+    elif command -v tmux >/dev/null 2>&1; then
+        run_distro_entry "host" run_host_interactive
+    else
+        info "tmux not found — skipping host interactive tests (install with: brew install tmux)"
+    fi
+
+    # Determine which distros to run
+    local run_distros=()
+    if [ -n "$TARGET_DISTRO" ]; then
+        local valid=false
+        for d in "${DISTROS[@]}"; do
+            if [ "$d" = "$TARGET_DISTRO" ]; then
+                valid=true
+                break
+            fi
+        done
+        if [ "$valid" = false ]; then
+            die "Unknown distro: ${TARGET_DISTRO}. Available: ${DISTROS[*]}"
+        fi
+        run_distros=("$TARGET_DISTRO")
+    else
+        run_distros=("${DISTROS[@]}")
+    fi
+
+    # Filter out distros without images for this architecture
+    local arch
+    arch="$(uname -m)"
+    local filtered_distros=()
+    for d in "${run_distros[@]}"; do
+        if [ "$d" = "arch" ] && [ "$arch" != "x86_64" ]; then
+            info "Skipping arch (no image for ${arch})"
+            printf '%s SKIP 0s\n' "$d" > "${RESULTS_DIR}/${d}.result"
+            continue
+        fi
+        filtered_distros+=("$d")
+    done
+    run_distros=("${filtered_distros[@]}")
+
+    # Phase 1: Build images sequentially (benefits from shared layer cache)
+    info "Building ${#run_distros[@]} container image(s)..."
+    for d in "${run_distros[@]}"; do
+        if ! build_image "$d"; then
+            printf '%b  ✗ %s build failed%b\n' "$C_RED" "$d" "$C_RESET" >&2
+            printf '%s FAIL 0s\n' "$d" > "${RESULTS_DIR}/${d}.result"
+        fi
+    done
+
+    # Phase 2: Run tests in parallel
+    local pids=()
+    local pid_distros=()
+    for d in "${run_distros[@]}"; do
+        # Skip distros that failed to build
+        [ -f "${RESULTS_DIR}/${d}.result" ] && continue
+
+        run_distro_entry "$d" run_container_test_phases "$d" &
+        pids+=($!)
+        pid_distros+=("$d")
+    done
+
+    if [ ${#pids[@]} -gt 0 ]; then
+        local distro_list
+        distro_list="$(IFS=' '; printf '%s' "${pid_distros[*]}")"
+        info "Running ${#pids[@]} distro(s) in parallel: ${distro_list}"
+        # Wait for all background jobs
+        local i=0
+        while [ "$i" -lt "${#pids[@]}" ]; do
+            wait "${pids[$i]}" 2>/dev/null || true
+            i=$((i + 1))
+        done
+    fi
+
+    print_summary
+}
+
+# Container test phases (without build — build is done in phase 1)
+run_container_test_phases() {
+    local distro="$1"
+    if ! run_tests "$distro"; then
+        return 1
+    fi
+    if ! run_interactive_tests "$distro"; then
+        return 1
+    fi
+}
+
+main "$@"

test/git-harden.bats

@@ -370,11 +370,12 @@ SSHEOF
 # Apply: git config settings (-y mode)
 # ===========================================================================
 
-@test "-y mode applies git config settings" {
+@test "-y mode applies setting group" {
     source_functions
     AUTO_YES=true
 
-    run apply_git_setting "transfer.fsckObjects" "true"
+    run apply_setting_group "Test Group" "Test description" \
+        "transfer.fsckObjects" "true" "Verify objects on transfer"
     assert_success
 
     local result
@@ -382,16 +383,17 @@ SSHEOF
     [ "$result" = "true" ]
 }
 
-@test "apply skips already-correct setting" {
+@test "apply_setting_group skips already-correct settings" {
     git config --global transfer.fsckObjects true
 
     source_functions
     AUTO_YES=true
 
-    run apply_git_setting "transfer.fsckObjects" "true"
+    run apply_setting_group "Test Group" "Test description" \
+        "transfer.fsckObjects" "true" "Verify objects on transfer"
     assert_success
-    # Should produce no output (no "Set" message)
-    refute_output --partial "Set"
+    # No changes needed — group should not print "Applied"
+    refute_output --partial "Applied"
 }
 
 # ===========================================================================
@@ -447,19 +449,27 @@ SSHEOF
     source_functions
     AUTO_YES=true
 
-    run apply_ssh_config
-    assert_success
+    apply_ssh_config
 
     # Check directory exists with correct mode
     [ -d "${TEST_HOME}/.ssh" ]
     [ -f "${TEST_HOME}/.ssh/config" ]
 
+    # stat format differs: macOS uses -f '%Lp', Linux uses -c '%a'
     local dir_perms
-    dir_perms="$(stat -f '%Lp' "${TEST_HOME}/.ssh" 2>/dev/null || stat -c '%a' "${TEST_HOME}/.ssh" 2>/dev/null)"
+    if stat -f '%Lp' "${TEST_HOME}/.ssh" >/dev/null 2>&1; then
+        dir_perms="$(stat -f '%Lp' "${TEST_HOME}/.ssh")"
+    else
+        dir_perms="$(stat -c '%a' "${TEST_HOME}/.ssh")"
+    fi
     [ "$dir_perms" = "700" ]
 
     local file_perms
-    file_perms="$(stat -f '%Lp' "${TEST_HOME}/.ssh/config" 2>/dev/null || stat -c '%a' "${TEST_HOME}/.ssh/config" 2>/dev/null)"
+    if stat -f '%Lp' "${TEST_HOME}/.ssh/config" >/dev/null 2>&1; then
+        file_perms="$(stat -f '%Lp' "${TEST_HOME}/.ssh/config")"
+    else
+        file_perms="$(stat -c '%a' "${TEST_HOME}/.ssh/config")"
+    fi
     [ "$file_perms" = "600" ]
 }
 
@@ -515,6 +525,37 @@ SSHEOF
     grep -q "HashKnownHosts no" "${TEST_HOME}/.ssh/config"
 }
 
+@test "audit recognises SSH directives using = separator" {
+    source_functions
+
+    cat > "${TEST_HOME}/.ssh/config" <<'SSHEOF'
+StrictHostKeyChecking=accept-new
+HashKnownHosts = yes
+SSHEOF
+
+    run audit_ssh_directive "StrictHostKeyChecking" "accept-new"
+    assert_output --partial "[OK]"
+
+    run audit_ssh_directive "HashKnownHosts" "yes"
+    assert_output --partial "[OK]"
+}
+
+@test "apply skips SSH directives using = separator when value matches" {
+    cat > "${TEST_HOME}/.ssh/config" <<'SSHEOF'
+StrictHostKeyChecking=accept-new
+SSHEOF
+
+    source_functions
+    AUTO_YES=true
+
+    apply_ssh_directive "StrictHostKeyChecking" "accept-new"
+
+    # Should still have exactly one occurrence
+    local count
+    count="$(grep -c "StrictHostKeyChecking" "${TEST_HOME}/.ssh/config")"
+    [ "$count" -eq 1 ]
+}
+
 # ===========================================================================
 # Signing: key detection
 # ===========================================================================
@@ -820,3 +861,302 @@ SSHEOF
     assert_output --partial "branch protection"
     assert_output --partial "vigilant mode"
 }
+
+# ===========================================================================
+# v0.2.0: New git config settings
+# ===========================================================================
+
+@test "audit reports new v0.2.0 settings as MISS on fresh config" {
+    source_functions
+    detect_platform
+    detect_credential_helper
+
+    run audit_git_config
+    assert_output --partial "user.useConfigOnly"
+    assert_output --partial "transfer.bundleURI"
+    assert_output --partial "fetch.prune"
+    assert_output --partial "protocol.version"
+    assert_output --partial "init.defaultBranch"
+    assert_output --partial "gc.reflogExpire"
+    assert_output --partial "gc.reflogExpireUnreachable"
+    assert_output --partial "core.symlinks"
+}
+
+@test "-y mode applies new v0.2.0 settings" {
+    run bash "$SCRIPT" -y
+    assert_success
+
+    [ "$(git config --global user.useConfigOnly)" = "true" ]
+    [ "$(git config --global transfer.bundleURI)" = "false" ]
+    [ "$(git config --global fetch.prune)" = "true" ]
+    [ "$(git config --global protocol.version)" = "2" ]
+    [ "$(git config --global init.defaultBranch)" = "main" ]
+    [ "$(git config --global gc.reflogExpire)" = "180.days" ]
+    [ "$(git config --global gc.reflogExpireUnreachable)" = "90.days" ]
+}
+
+@test "-y mode does NOT apply core.symlinks" {
+    run bash "$SCRIPT" -y
+    assert_success
+
+    local symlinks
+    symlinks="$(git config --global --get core.symlinks 2>/dev/null || echo "unset")"
+    [ "$symlinks" = "unset" ]
+}
+
+# ===========================================================================
+# v0.2.0: safe.directory wildcard detection
+# ===========================================================================
+
+@test "audit detects safe.directory = * wildcard" {
+    source_functions
+    detect_platform
+    detect_credential_helper
+
+    git config --global safe.directory '*'
+
+    run audit_git_config
+    assert_output --partial "safe.directory = * disables ownership checks"
+}
+
+@test "audit does not warn without safe.directory wildcard" {
+    source_functions
+    detect_platform
+    detect_credential_helper
+
+    git config --global safe.directory "/some/path"
+
+    run audit_git_config
+    refute_output --partial "safe.directory = * disables"
+}
+
+@test "-y mode removes safe.directory = * wildcard" {
+    git config --global safe.directory '*'
+
+    run bash "$SCRIPT" -y
+    assert_success
+
+    local safe_dirs
+    safe_dirs="$(git config --global --get-all safe.directory 2>/dev/null || echo "none")"
+    refute [ "$safe_dirs" = "*" ]
+}
+
+# ===========================================================================
+# v0.2.0: Pre-commit hook
+# ===========================================================================
+
+@test "audit reports MISS when no pre-commit hook exists" {
+    source_functions
+
+    run audit_precommit_hook
+    assert_output --partial "No pre-commit hook"
+}
+
+@test "audit reports OK when gitleaks hook exists" {
+    source_functions
+
+    mkdir -p "${HOME}/.config/git/hooks"
+    cat > "${HOME}/.config/git/hooks/pre-commit" << 'EOF'
+#!/usr/bin/env bash
+gitleaks protect --staged
+EOF
+    chmod +x "${HOME}/.config/git/hooks/pre-commit"
+
+    run audit_precommit_hook
+    assert_output --partial "[OK]"
+    assert_output --partial "gitleaks"
+}
+
+@test "audit reports WARN for non-gitleaks hook" {
+    source_functions
+
+    mkdir -p "${HOME}/.config/git/hooks"
+    printf '#!/usr/bin/env bash\necho custom hook\n' > "${HOME}/.config/git/hooks/pre-commit"
+    chmod +x "${HOME}/.config/git/hooks/pre-commit"
+
+    run audit_precommit_hook
+    assert_output --partial "does not reference gitleaks"
+}
+
+@test "apply does not overwrite existing pre-commit hook" {
+    source_functions
+    AUTO_YES=true
+
+    mkdir -p "${HOME}/.config/git/hooks"
+    printf '#!/usr/bin/env bash\necho my hook\n' > "${HOME}/.config/git/hooks/pre-commit"
+
+    run apply_precommit_hook
+    assert_output --partial "not overwriting"
+
+    # Verify original content preserved
+    run cat "${HOME}/.config/git/hooks/pre-commit"
+    assert_output --partial "my hook"
+}
+
+# ===========================================================================
+# v0.2.0: Global gitignore
+# ===========================================================================
+
+@test "audit reports MISS when no excludesFile configured" {
+    source_functions
+
+    run audit_global_gitignore
+    assert_output --partial "no global gitignore configured"
+}
+
+@test "audit reports OK when excludesFile has security patterns" {
+    source_functions
+
+    mkdir -p "${HOME}/.config/git"
+    printf '.env\n*.pem\n*.key\n' > "${HOME}/.config/git/ignore"
+    git config --global core.excludesFile "~/.config/git/ignore"
+
+    run audit_global_gitignore
+    assert_output --partial "[OK]"
+    assert_output --partial "contains security patterns"
+}
+
+@test "audit warns when excludesFile lacks security patterns" {
+    source_functions
+
+    mkdir -p "${HOME}/.config/git"
+    printf '*.log\n*.tmp\n' > "${HOME}/.config/git/ignore"
+    git config --global core.excludesFile "~/.config/git/ignore"
+
+    run audit_global_gitignore
+    assert_output --partial "lacks secret patterns"
+}
+
+@test "-y mode creates global gitignore" {
+    run bash "$SCRIPT" -y
+    assert_success
+
+    [ -f "${HOME}/.config/git/ignore" ]
+    run cat "${HOME}/.config/git/ignore"
+    assert_output --partial ".env"
+    assert_output --partial "*.pem"
+    assert_output --partial "*.key"
+    assert_output --partial "!.env.example"
+
+    [ "$(git config --global core.excludesFile)" = "~/.config/git/ignore" ]
+}
+
+@test "-y mode skips gitignore when excludesFile already set" {
+    git config --global core.excludesFile "/some/other/path"
+
+    run bash "$SCRIPT" -y
+    assert_success
+
+    [ "$(git config --global core.excludesFile)" = "/some/other/path" ]
+}
+
+# ===========================================================================
+# v0.2.0: Credential hygiene
+# ===========================================================================
+
+@test "audit warns about ~/.git-credentials" {
+    source_functions
+
+    printf 'https://user:token@github.com\n' > "${HOME}/.git-credentials"
+
+    run audit_credential_hygiene
+    assert_output --partial "git-credentials"
+    assert_output --partial "plaintext"
+}
+
+@test "audit warns about ~/.netrc" {
+    source_functions
+
+    printf 'machine github.com\nlogin user\npassword token\n' > "${HOME}/.netrc"
+
+    run audit_credential_hygiene
+    assert_output --partial ".netrc"
+}
+
+@test "audit warns about ~/.npmrc with auth token" {
+    source_functions
+
+    printf '//registry.npmjs.org/:_authToken=npm_abcdef123456\n' > "${HOME}/.npmrc"
+
+    run audit_credential_hygiene
+    assert_output --partial "npm registry token"
+}
+
+@test "audit does not warn about ~/.npmrc without token" {
+    source_functions
+
+    printf 'registry=https://registry.npmjs.org/\n' > "${HOME}/.npmrc"
+
+    run audit_credential_hygiene
+    refute_output --partial "npm registry token"
+}
+
+@test "audit warns about ~/.pypirc with password" {
+    source_functions
+
+    printf '[pypi]\nusername = user\npassword = secret123\n' > "${HOME}/.pypirc"
+
+    run audit_credential_hygiene
+    assert_output --partial "PyPI credentials"
+}
+
+@test "audit no warnings with clean credential state" {
+    source_functions
+
+    run audit_credential_hygiene
+    refute_output --partial "[WARN]"
+}
+
+# ===========================================================================
+# v0.2.0: SSH key hygiene
+# ===========================================================================
+
+@test "SSH key hygiene: ed25519 reported as OK" {
+    source_functions
+
+    ssh-keygen -t ed25519 -f "${HOME}/.ssh/test_ed25519" -N "" -q
+    run audit_ssh_key_hygiene
+    assert_output --partial "[OK]"
+    assert_output --partial "ed25519"
+}
+
+@test "SSH key hygiene: RSA key reported as WARN" {
+    source_functions
+
+    ssh-keygen -t rsa -b 2048 -f "${HOME}/.ssh/test_rsa" -N "" -q
+    run audit_ssh_key_hygiene
+    assert_output --partial "[WARN]"
+    assert_output --partial "RSA"
+    assert_output --partial "migrating to ed25519"
+}
+
+@test "SSH key hygiene: no keys produces info message" {
+    source_functions
+
+    # Remove the default keys created in setup (there are none)
+    rm -f "${HOME}/.ssh/"*.pub
+
+    run audit_ssh_key_hygiene
+    assert_output --partial "No SSH public keys found"
+}
+
+@test "SSH key hygiene: picks up keys from IdentityFile in ssh config" {
+    source_functions
+
+    mkdir -p "${HOME}/.ssh/custom"
+    ssh-keygen -t ed25519 -f "${HOME}/.ssh/custom/my_key" -N "" -q
+    printf 'IdentityFile ~/.ssh/custom/my_key\n' > "${HOME}/.ssh/config"
+
+    run audit_ssh_key_hygiene
+    assert_output --partial "[OK]"
+    assert_output --partial "my_key"
+}
+
+# ===========================================================================
+# v0.2.0: Version bump
+# ===========================================================================
+
+@test "--version reports 0.2.3" {
+    run bash "$SCRIPT" --version
+    assert_output --partial "0.2.3"
+}

test/interactive/helpers.sh

@@ -0,0 +1,109 @@
+#!/usr/bin/env bash
+# Shared helpers for interactive tmux-driven tests
+
+set -o errexit
+set -o nounset
+set -o pipefail
+IFS=$'\n\t'
+
+TMUX_SESSION="test-$$"
+readonly SCRIPT_PATH="${HOME}/git-harden.sh"
+
+# Colors
+if [ -t 2 ]; then
+    readonly C_RED='\033[0;31m'
+    readonly C_GREEN='\033[0;32m'
+    readonly C_RESET='\033[0m'
+else
+    readonly C_RED=''
+    readonly C_GREEN=''
+    readonly C_RESET=''
+fi
+
+# Wait for a string to appear in the tmux pane.
+# Polls every 0.2s, times out after $2 seconds (default 10).
+wait_for() {
+    local pattern="$1"
+    local timeout="${2:-10}"
+    local elapsed=0
+    while ! tmux capture-pane -t "$TMUX_SESSION" -p | grep -qF "$pattern"; do
+        sleep 0.2
+        elapsed=$(( elapsed + 1 ))
+        if (( elapsed > timeout * 5 )); then
+            printf 'TIMEOUT waiting for: %s\n' "$pattern" >&2
+            printf 'Current pane content:\n' >&2
+            tmux capture-pane -t "$TMUX_SESSION" -p >&2
+            return 1
+        fi
+    done
+}
+
+# Send keys to the tmux session
+send() {
+    tmux send-keys -t "$TMUX_SESSION" "$@"
+}
+
+# Start git-harden.sh in a tmux session.
+# Explicitly pass HOME and GIT_CONFIG_GLOBAL — tmux spawns a login shell
+# which resets HOME from the passwd entry, breaking the isolated test env.
+start_session() {
+    tmux kill-session -t "$TMUX_SESSION" 2>/dev/null || true
+    sleep 0.5
+    local env_setup="export HOME='${HOME}';"
+    if [ -n "${GIT_CONFIG_GLOBAL:-}" ]; then
+        env_setup="${env_setup} export GIT_CONFIG_GLOBAL='${GIT_CONFIG_GLOBAL}';"
+    fi
+    tmux new-session -d -s "$TMUX_SESSION" \
+        "${env_setup} bash '${SCRIPT_PATH}'"
+    # Keep the pane alive after the script exits so capture_output can read it
+    tmux set-option -t "$TMUX_SESSION" remain-on-exit on
+    sleep 0.5
+    # Verify session started
+    if ! tmux has-session -t "$TMUX_SESSION" 2>/dev/null; then
+        printf 'ERROR: tmux session "%s" failed to start\n' "$TMUX_SESSION" >&2
+        printf 'SCRIPT_PATH=%s\n' "$SCRIPT_PATH" >&2
+        printf 'HOME=%s\n' "$HOME" >&2
+        return 1
+    fi
+}
+
+# Wait for the script to exit and capture final output
+capture_output() {
+    # Wait for the shell to become available (script exited)
+    local timeout=30
+    local elapsed=0
+    while tmux list-panes -t "$TMUX_SESSION" -F '#{pane_dead}' 2>/dev/null | grep -q '^0$'; do
+        sleep 0.5
+        elapsed=$(( elapsed + 1 ))
+        if (( elapsed > timeout * 2 )); then
+            printf 'TIMEOUT waiting for script to exit\n' >&2
+            tmux capture-pane -t "$TMUX_SESSION" -p >&2
+            return 1
+        fi
+    done
+    tmux capture-pane -t "$TMUX_SESSION" -p
+}
+
+# Clean up
+cleanup() {
+    tmux kill-session -t "$TMUX_SESSION" 2>/dev/null || true
+}
+
+# Assert helper
+assert_contains() {
+    local haystack="$1"
+    local needle="$2"
+    if printf '%s' "$haystack" | grep -qF "$needle"; then
+        return 0
+    fi
+    printf '%bFAIL:%b expected output to contain: %s\n' "$C_RED" "$C_RESET" "$needle" >&2
+    return 1
+}
+
+pass() {
+    printf '%b  PASS:%b %s\n' "$C_GREEN" "$C_RESET" "$1" >&2
+}
+
+fail() {
+    printf '%b  FAIL:%b %s\n' "$C_RED" "$C_RESET" "$1" >&2
+}

test/interactive/run-all.sh

@@ -0,0 +1,30 @@
+#!/usr/bin/env bash
+# Run all interactive tmux-driven tests
+# Intended to be run inside a container (with tmux installed)
+
+set -o nounset
+set -o pipefail
+IFS=$'\n\t'
+
+SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd)"
+
+passed=0
+failed=0
+total=0
+
+for test_script in "${SCRIPT_DIR}"/test-*.sh; do
+    [ -f "$test_script" ] || continue
+    total=$((total + 1))
+    printf '\n── %s ──\n' "$(basename "$test_script")" >&2
+    if bash "$test_script"; then
+        passed=$((passed + 1))
+    else
+        failed=$((failed + 1))
+    fi
+done
+
+printf '\n── Interactive tests: %d passed, %d failed, %d total ──\n' "$passed" "$failed" "$total" >&2
+
+if [ "$failed" -gt 0 ]; then
+    exit 1
+fi

test/interactive/test-full-accept.sh

@@ -0,0 +1,62 @@
+#!/usr/bin/env bash
+# Interactive test: accept all prompts (safety gate + hardening + signing skip)
+# Verifies: all settings applied, re-audit exits 0
+
+set -o errexit
+set -o nounset
+set -o pipefail
+IFS=$'\n\t'
+
+SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd)"
+# shellcheck source=helpers.sh
+source "${SCRIPT_DIR}/helpers.sh"
+
+main() {
+    trap cleanup EXIT
+
+    printf 'Test: Full interactive apply (accept all)\n' >&2
+
+    start_session
+
+    # Safety review gate — answer yes
+    wait_for "reviewed this script"
+    send "y" Enter
+
+    # Proceed with hardening — answer yes
+    wait_for "Proceed with hardening"
+    send "y" Enter
+
+    # Accept each setting prompt by sending "y" + Enter repeatedly.
+    # v0.2.0 adds more prompts (pre-commit hook, gitignore, core.symlinks),
+    # so we need enough iterations to get through all of them.
+    local pane_content
+    for _ in $(seq 1 50); do
+        sleep 0.3
+        pane_content="$(tmux capture-pane -t "$TMUX_SESSION" -p 2>/dev/null || true)"
+        if printf '%s' "$pane_content" | grep -qF "Signing key options"; then
+            break
+        fi
+        if printf '%s' "$pane_content" | grep -qF "Hardening complete"; then
+            break
+        fi
+        send "y" Enter
+    done
+
+    # Signing wizard — skip
+    wait_for "Signing key options" 20
+    send "s" Enter
+
+    # Wait for completion
+    sleep 2
+    capture_output >/dev/null 2>&1 || true
+
+    # Verify: re-run audit — signing won't pass (skipped) but git config should
+    if git config --global --get transfer.fsckObjects | grep -q true; then
+        pass "Full accept: git config settings applied (signing skipped as expected)"
+    else
+        fail "Full accept: settings not applied"
+        exit 1
+    fi
+}
+
+main

test/interactive/test-safety-gate-decline.sh

@@ -0,0 +1,49 @@
+#!/usr/bin/env bash
+# Interactive test: decline safety review gate
+# Verifies: script exits 0, prints AI review instructions, no config changes
+
+set -o errexit
+set -o nounset
+set -o pipefail
+IFS=$'\n\t'
+
+SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd)"
+# shellcheck source=helpers.sh
+source "${SCRIPT_DIR}/helpers.sh"
+
+main() {
+    trap cleanup EXIT
+
+    printf 'Test: Safety gate decline\n' >&2
+
+    # Snapshot current config
+    local config_before
+    config_before="$(git config --global --list 2>/dev/null || true)"
+
+    start_session
+
+    # Safety review gate — answer no (default)
+    wait_for "reviewed this script"
+    send "n" Enter
+
+    # Wait for exit
+    sleep 2
+    local output
+    output="$(capture_output)"
+
+    # Verify: output contains AI review instructions
+    assert_contains "$output" "claude"
+    assert_contains "$output" "gemini"
+
+    # Verify: no config changes
+    local config_after
+    config_after="$(git config --global --list 2>/dev/null || true)"
+    if [ "$config_before" = "$config_after" ]; then
+        pass "Safety gate decline: no config changes, instructions shown"
+    else
+        fail "Safety gate decline: config was modified"
+        exit 1
+    fi
+}
+
+main

test/interactive/test-signing-generate.sh

@@ -0,0 +1,93 @@
+#!/usr/bin/env bash
+# Interactive test: generate ed25519 key via signing wizard
+# Verifies: key created, user.signingkey configured, commit.gpgsign=true
+
+set -o errexit
+set -o nounset
+set -o pipefail
+IFS=$'\n\t'
+
+SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd)"
+# shellcheck source=helpers.sh
+source "${SCRIPT_DIR}/helpers.sh"
+
+main() {
+    trap cleanup EXIT
+
+    printf 'Test: Signing wizard - generate ed25519 key\n' >&2
+
+    # Ensure no existing keys
+    rm -f "${HOME}/.ssh/id_ed25519" "${HOME}/.ssh/id_ed25519.pub"
+
+    start_session
+
+    # Safety review gate
+    wait_for "reviewed this script"
+    send "y" Enter
+
+    # Proceed with hardening
+    wait_for "Proceed with hardening"
+    send "y" Enter
+
+    # Accept settings until signing wizard (v0.2.0 adds more prompts)
+    local pane_content
+    for _ in $(seq 1 50); do
+        sleep 0.3
+        pane_content="$(tmux capture-pane -t "$TMUX_SESSION" -p 2>/dev/null || true)"
+        if printf '%s' "$pane_content" | grep -qF "Signing key options"; then
+            break
+        fi
+        if printf '%s' "$pane_content" | grep -qF "Hardening complete"; then
+            break
+        fi
+        send "y" Enter
+    done
+
+    # Signing wizard — option 1: generate ed25519
+    wait_for "Signing key options" 20
+    send "1" Enter
+
+    # ssh-keygen prompts for passphrase — enter empty twice
+    wait_for "Enter passphrase" 10
+    send "" Enter
+    wait_for "Enter same passphrase" 10
+    send "" Enter
+
+    # Signing wizard asks "Enable commit and tag signing?" — accept
+    wait_for "Enable commit and tag signing" 10
+    send "y" Enter
+
+    # Wait for completion
+    sleep 3
+    capture_output >/dev/null 2>&1 || true
+
+    # Verify key exists
+    if [ -f "${HOME}/.ssh/id_ed25519.pub" ]; then
+        pass "Key generated: ~/.ssh/id_ed25519.pub exists"
+    else
+        fail "Key not generated"
+        exit 1
+    fi
+
+    # Verify signing key configured
+    local signing_key
+    signing_key="$(git config --global --get user.signingkey 2>/dev/null || true)"
+    if [ -n "$signing_key" ]; then
+        pass "user.signingkey configured: ${signing_key}"
+    else
+        fail "user.signingkey not configured"
+        exit 1
+    fi
+
+    # Verify gpgsign enabled
+    local gpgsign
+    gpgsign="$(git config --global --get commit.gpgsign 2>/dev/null || true)"
+    if [ "$gpgsign" = "true" ]; then
+        pass "commit.gpgsign=true"
+    else
+        fail "commit.gpgsign not set"
+        exit 1
+    fi
+}
+
+main

test/interactive/test-signing-skip.sh

@@ -0,0 +1,78 @@
+#!/usr/bin/env bash
+# Interactive test: skip signing wizard
+# Verifies: no signing key configured, commit.gpgsign not set
+
+set -o errexit
+set -o nounset
+set -o pipefail
+IFS=$'\n\t'
+
+SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd)"
+# shellcheck source=helpers.sh
+source "${SCRIPT_DIR}/helpers.sh"
+
+main() {
+    trap cleanup EXIT
+
+    printf 'Test: Signing wizard - skip\n' >&2
+
+    # Remove any keys from prior tests so wizard shows key generation options
+    rm -f "${HOME}/.ssh/id_ed25519" "${HOME}/.ssh/id_ed25519.pub"
+    rm -f "${HOME}/.ssh/id_ed25519_sk" "${HOME}/.ssh/id_ed25519_sk.pub"
+    git config --global --unset user.signingkey 2>/dev/null || true
+    git config --global --unset commit.gpgsign 2>/dev/null || true
+
+    start_session
+
+    # Safety review gate
+    wait_for "reviewed this script"
+    send "y" Enter
+
+    # Proceed with hardening
+    wait_for "Proceed with hardening"
+    send "y" Enter
+
+    # Accept settings until signing wizard (v0.2.0 adds more prompts)
+    local pane_content
+    for _ in $(seq 1 50); do
+        sleep 0.3
+        pane_content="$(tmux capture-pane -t "$TMUX_SESSION" -p 2>/dev/null || true)"
+        if printf '%s' "$pane_content" | grep -qF "Signing key options"; then
+            break
+        fi
+        if printf '%s' "$pane_content" | grep -qF "Hardening complete"; then
+            break
+        fi
+        send "y" Enter
+    done
+
+    # Signing wizard — skip
+    wait_for "Signing key options" 20
+    send "s" Enter
+
+    # Wait for completion
+    sleep 2
+    capture_output >/dev/null 2>&1 || true
+
+    # Verify: no signing key
+    local signing_key
+    signing_key="$(git config --global --get user.signingkey 2>/dev/null || true)"
+    if [ -z "$signing_key" ]; then
+        pass "Signing skip: user.signingkey not set"
+    else
+        fail "Signing skip: user.signingkey was set unexpectedly: ${signing_key}"
+        exit 1
+    fi
+
+    # Verify: commit.gpgsign not set
+    local gpgsign
+    gpgsign="$(git config --global --get commit.gpgsign 2>/dev/null || true)"
+    if [ -z "$gpgsign" ]; then
+        pass "Signing skip: commit.gpgsign not set"
+    else
+        fail "Signing skip: commit.gpgsign was set unexpectedly: ${gpgsign}"
+        exit 1
+    fi
+}
+
+main

test/run-interactive.sh

@@ -0,0 +1,52 @@
+#!/usr/bin/env bash
+# Run interactive tmux tests on the host in an isolated HOME.
+# Covers macOS ssh-keygen and platform-specific behavior that
+# cannot be tested inside Linux containers.
+#
+# Requires: tmux, git, ssh-keygen
+
+set -o errexit
+set -o nounset
+set -o pipefail
+IFS=$'\n\t'
+
+SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd)"
+readonly SCRIPT_DIR
+REPO_ROOT="$(cd "${SCRIPT_DIR}/.." && pwd)"
+readonly REPO_ROOT
+
+die() {
+    printf 'Error: %s\n' "$1" >&2
+    exit 1
+}
+
+# Check dependencies
+command -v tmux >/dev/null 2>&1 || die "tmux is required. Install with: brew install tmux"
+command -v git >/dev/null 2>&1 || die "git is required"
+command -v ssh-keygen >/dev/null 2>&1 || die "ssh-keygen is required"
+
+# Create isolated HOME
+TEST_HOME="$(mktemp -d)"
+trap 'rm -rf "$TEST_HOME"' EXIT
+
+# Set up the isolated environment
+export HOME="$TEST_HOME"
+export GIT_CONFIG_GLOBAL="${TEST_HOME}/.gitconfig"
+
+mkdir -p "${TEST_HOME}/.ssh"
+mkdir -p "${TEST_HOME}/.config/git"
+
+# Copy the script into the test home (interactive helpers expect it at ~/git-harden.sh)
+cp "${REPO_ROOT}/git-harden.sh" "${TEST_HOME}/git-harden.sh"
+
+# Copy interactive test scripts
+cp -r "${SCRIPT_DIR}/interactive" "${TEST_HOME}/test-interactive"
+
+# Set up minimal git config
+git config --global user.name "Test User"
+git config --global user.email "test@example.com"
+
+printf '── Running interactive tests on host (%s) ──\n' "$(uname -s)" >&2
+
+# Run the interactive tests
+exec bash "${TEST_HOME}/test-interactive/run-all.sh"