Claude-skill-registry git-security-2025
Git security best practices for 2025 including signed commits, zero-trust workflows, secret scanning, and verification
git clone https://github.com/majiayu000/claude-skill-registry
T=$(mktemp -d) && git clone --depth=1 https://github.com/majiayu000/claude-skill-registry "$T" && mkdir -p ~/.claude/skills && cp -r "$T/skills/data/git-security-2025" ~/.claude/skills/majiayu000-claude-skill-registry-git-security-2025 && rm -rf "$T"
skills/data/git-security-2025/SKILL.md🚨 CRITICAL GUIDELINES
Windows File Path Requirements
MANDATORY: Always Use Backslashes on Windows for File Paths
When using Edit or Write tools on Windows, you MUST use backslashes (
\) in file paths, NOT forward slashes (/).
Examples:
- ❌ WRONG:
D:/repos/project/file.tsx - ✅ CORRECT:
D:\repos\project\file.tsx
This applies to:
- Edit tool file_path parameter
- Write tool file_path parameter
- All file operations on Windows systems
Documentation Guidelines
NEVER create new documentation files unless explicitly requested by the user.
- Priority: Update existing README.md files rather than creating new documentation
- Repository cleanliness: Keep repository root clean - only README.md unless user requests otherwise
- Style: Documentation should be concise, direct, and professional - avoid AI-generated tone
- User preference: Only create additional .md files when user specifically asks for documentation
Git Security Best Practices 2025
Zero-Trust Security Model (2025 Standard)
What: Every developer identity must be authenticated and authorized explicitly. All Git operations are logged, signed, and continuously monitored.
Core Principles:
- Never trust, always verify - Every commit verified
- Least privilege access - Minimal permissions required
- Continuous monitoring - All operations logged and audited
- Assume breach - Defense in depth strategies
Implementing Zero-Trust for Git
1. Mandatory Signed Commits:
# Global requirement git config --global commit.gpgsign true git config --global tag.gpgsign true # Enforce via branch protection (GitHub/GitLab/Azure DevOps) # Repository Settings → Branches → Require signed commits
2. Identity Verification:
# Every commit must verify identity git log --show-signature -10 # Reject unsigned commits in CI/CD # .github/workflows/verify.yml - name: Verify all commits are signed run: | git log --pretty="%H" origin/main..HEAD | while read commit; do if ! git verify-commit "$commit" 2>/dev/null; then echo "ERROR: Unsigned commit $commit" exit 1 fi done
3. Continuous Audit Logging:
# Enable Git audit trail git config --global alias.audit 'log --all --pretty="%H|%an|%ae|%ad|%s|%GK" --date=iso' # Export audit log git audit > git-audit.log # Monitor for suspicious activity git log --author="*" --since="24 hours ago" --pretty=format:"%an %ae %s"
4. Least Privilege Access:
# GitHub branch protection (zero-trust model) branches: main: protection_rules: required_pull_request_reviews: true dismiss_stale_reviews: true require_code_owner_reviews: true required_approving_review_count: 2 require_signed_commits: true enforce_admins: true restrictions: users: [] # No direct push teams: ["security-team"]
5. Continuous Monitoring:
# Monitor all repository changes # .github/workflows/security-monitor.yml name: Security Monitoring on: [push, pull_request] jobs: monitor: runs-on: ubuntu-latest steps: - uses: actions/checkout@v4 with: fetch-depth: 0 - name: Check for unsigned commits run: git verify-commit HEAD || echo "::warning::Unsigned commit detected" - name: Scan for secrets run: gitleaks detect --exit-code 1 - name: Check commit author run: | AUTHOR=$(git log -1 --format='%an <%ae>') echo "Commit by: $AUTHOR" # Log to SIEM/security monitoring
Signed Commits (Mandatory in 2025)
Why: Cryptographically verify commit authorship, prevent impersonation, ensure audit trail.
Industry Trend: Signed commits increasingly required in 2025 workflows.
GPG Signing (Traditional)
Setup:
# Generate GPG key gpg --full-generate-key # Choose: RSA and RSA, 4096 bits, expires in 2y # List keys gpg --list-secret-keys --keyid-format=long # Example output: # sec rsa4096/ABC123DEF456 2025-01-15 [SC] [expires: 2027-01-15] # uid [ultimate] Your Name <your.email@example.com> # ssb rsa4096/GHI789JKL012 2025-01-15 [E] [expires: 2027-01-15] # Configure Git git config --global user.signingkey ABC123DEF456 git config --global commit.gpgsign true git config --global tag.gpgsign true # Export public key for GitHub/GitLab gpg --armor --export ABC123DEF456 # Copy output and add to GitHub/GitLab/Bitbucket # Sign commits git commit -S -m "feat: add authentication" # Verify signatures git log --show-signature git verify-commit HEAD git verify-tag v1.0.0
Troubleshooting:
# GPG agent not running export GPG_TTY=$(tty) echo 'export GPG_TTY=$(tty)' >> ~/.bashrc # Cache passphrase longer echo 'default-cache-ttl 34560000' >> ~/.gnupg/gpg-agent.conf echo 'max-cache-ttl 34560000' >> ~/.gnupg/gpg-agent.conf gpg-connect-agent reloadagent /bye # Test signing echo "test" | gpg --clearsign
SSH Signing (Modern Alternative - 2023+)
Why SSH: Simpler, reuse existing SSH keys, no GPG required.
Setup:
# Check if SSH key exists ls -la ~/.ssh/id_ed25519.pub # Generate if needed ssh-keygen -t ed25519 -C "your.email@example.com" # Configure Git to use SSH signing git config --global gpg.format ssh git config --global user.signingkey ~/.ssh/id_ed25519.pub git config --global commit.gpgsign true # Add public key to GitHub cat ~/.ssh/id_ed25519.pub # GitHub Settings → SSH and GPG keys → New SSH key → Key type: Signing Key # Sign commits (automatic with commit.gpgsign=true) git commit -m "feat: add feature" # Verify git log --show-signature
Configure allowed signers file (for verification):
# Create allowed signers file echo "your.email@example.com $(cat ~/.ssh/id_ed25519.pub)" > ~/.ssh/allowed_signers # Configure Git git config --global gpg.ssh.allowedSignersFile ~/.ssh/allowed_signers # Verify commits git verify-commit HEAD
Secret Scanning & Prevention
GitHub Secret Scanning (Push Protection)
Enable in repository:
- Settings → Code security → Secret scanning → Enable
- Enable push protection (blocks secrets at push time)
AI-powered detection (2025):
- AWS credentials
- Azure service principals
- Google Cloud keys
- GitHub tokens
- Database connection strings
- API keys (OpenAI, Stripe, Anthropic, etc.)
- Private keys
- OAuth tokens
- Custom patterns
Example blocked push:
$ git push remote: error: GH013: Repository rule violations found for refs/heads/main. remote: remote: - Push cannot contain secrets remote: remote: Resolve the following violations before pushing again remote: remote: — AWS Access Key remote: locations: remote: - config.py:12 remote: remote: (Disable push protection: https://github.com/settings/security_analysis) remote: To github.com:user/repo.git ! [remote rejected] main -> main (push declined due to repository rule violations)
Fix:
# Remove secret from file # Use environment variable instead echo "AWS_ACCESS_KEY=your_key" >> .env echo ".env" >> .gitignore # Remove from history if already committed git rm --cached config.py git commit -m "Remove secrets" # If in history, use filter-repo git filter-repo --path config.py --invert-paths git push --force
Gitleaks (Local Scanning)
Install:
# macOS brew install gitleaks # Linux wget https://github.com/gitleaks/gitleaks/releases/download/v8.18.0/gitleaks_8.18.0_linux_x64.tar.gz tar -xzf gitleaks_8.18.0_linux_x64.tar.gz sudo mv gitleaks /usr/local/bin/ # Windows choco install gitleaks
Usage:
# Scan entire repository gitleaks detect # Scan uncommitted changes gitleaks protect # Scan specific directory gitleaks detect --source ./src # Generate report gitleaks detect --report-format json --report-path gitleaks-report.json # Use in CI/CD gitleaks detect --exit-code 1
Pre-commit hook:
# .git/hooks/pre-commit #!/bin/bash gitleaks protect --staged --verbose if [ $? -ne 0 ]; then echo "⚠️ Gitleaks detected secrets. Commit blocked." exit 1 fi
Git-secrets (AWS-focused)
# Install brew install git-secrets # macOS # or git clone https://github.com/awslabs/git-secrets.git cd git-secrets sudo make install # Initialize in repository git secrets --install git secrets --register-aws # Add custom patterns git secrets --add 'password\s*=\s*[^\s]+' git secrets --add 'api[_-]?key\s*=\s*[^\s]+' # Scan git secrets --scan git secrets --scan-history
Enforce Signed Commits
Branch Protection Rules
GitHub:
Repository → Settings → Branches → Branch protection rules ☑ Require signed commits ☑ Require linear history ☑ Require status checks to pass
GitLab:
Repository → Settings → Repository → Protected branches ☑ Allowed to push: No one ☑ Allowed to merge: Maintainers ☑ Require all commits be signed
Azure DevOps:
Branch Policies → Add policy → Require signed commits
Pre-receive Hook (Server-side enforcement)
#!/bin/bash # .git/hooks/pre-receive (on server) zero_commit="0000000000000000000000000000000000000000" while read oldrev newrev refname; do # Skip branch deletion if [ "$newrev" = "$zero_commit" ]; then continue fi # Check all commits in push for commit in $(git rev-list "$oldrev".."$newrev"); do # Verify commit signature if ! git verify-commit "$commit" 2>/dev/null; then echo "Error: Commit $commit is not signed" echo "All commits must be signed. Configure with:" echo " git config commit.gpgsign true" exit 1 fi done done exit 0
Security Configuration
Recommended Git Config
# Enforce signed commits git config --global commit.gpgsign true git config --global tag.gpgsign true # Use SSH signing (modern) git config --global gpg.format ssh git config --global user.signingkey ~/.ssh/id_ed25519.pub # Security settings git config --global protocol.version 2 git config --global transfer.fsckobjects true git config --global fetch.fsckobjects true git config --global receive.fsckobjects true # Prevent credential leaks git config --global credential.helper cache --timeout=3600 # Or use system credential manager git config --global credential.helper wincred # Windows git config --global credential.helper osxkeychain # macOS # Line ending safety git config --global core.autocrlf true # Windows git config --global core.autocrlf input # macOS/Linux # Editor safety (avoid nano/vim leaks) git config --global core.editor "code --wait"
.gitignore Security
# Secrets .env .env.* *.pem *.key *.p12 *.pfx *_rsa *_dsa *_ecdsa *_ed25519 credentials.json secrets.yaml config/secrets.yml # Cloud provider .aws/ .azure/ .gcloud/ gcloud-service-key.json # Databases *.sqlite *.db # Logs (may contain sensitive data) *.log logs/ # IDE secrets .vscode/settings.json .idea/workspace.xml # Build artifacts (may contain embedded secrets) dist/ build/ node_modules/ vendor/
Credential Management
SSH Keys
# Generate secure SSH key ssh-keygen -t ed25519 -C "your.email@example.com" -f ~/.ssh/id_ed25519_work # Use ed25519 (modern, secure, fast) # Avoid RSA < 4096 bits # Avoid DSA (deprecated) # Configure SSH agent eval "$(ssh-agent -s)" ssh-add ~/.ssh/id_ed25519_work # Test connection ssh -T git@github.com # Use different keys for different services # ~/.ssh/config Host github.com IdentityFile ~/.ssh/id_ed25519_github Host gitlab.com IdentityFile ~/.ssh/id_ed25519_gitlab
HTTPS Credentials
# Use credential manager (not plaintext!) # Windows git config --global credential.helper wincred # macOS git config --global credential.helper osxkeychain # Linux (libsecret) git config --global credential.helper /usr/share/git/credential/libsecret/git-credential-libsecret # Cache for limited time (temporary projects) git config --global credential.helper 'cache --timeout=3600'
Personal Access Tokens (PAT)
GitHub:
- Settings → Developer settings → Personal access tokens → Fine-grained tokens
- Set expiration (max 1 year)
- Minimum scopes needed
- Use for HTTPS authentication
Never commit tokens:
# Use environment variable export GITHUB_TOKEN="ghp_xxxxxxxxxxxx" git clone https://$GITHUB_TOKEN@github.com/user/repo.git # Or use Git credential helper gh auth login # GitHub CLI method
CodeQL & Security Scanning
GitHub CodeQL
.github/workflows/codeql.yml:
name: "CodeQL Security Scan" on: push: branches: [ main, develop ] pull_request: branches: [ main ] schedule: - cron: '0 0 * * 1' # Weekly scan jobs: analyze: name: Analyze runs-on: ubuntu-latest permissions: security-events: write contents: read strategy: fail-fast: false matrix: language: [ 'javascript', 'python', 'java' ] steps: - name: Checkout repository uses: actions/checkout@v4 - name: Initialize CodeQL uses: github/codeql-action/init@v3 with: languages: ${{ matrix.language }} queries: security-and-quality - name: Autobuild uses: github/codeql-action/autobuild@v3 - name: Perform CodeQL Analysis uses: github/codeql-action/analyze@v3 with: category: "/language:${{ matrix.language }}"
Detects:
- SQL injection
- XSS vulnerabilities
- Path traversal
- Command injection
- Insecure deserialization
- Authentication bypass
- Hardcoded secrets
Audit Trail
Enable detailed logging
# Log all Git operations git config --global alias.ll 'log --all --graph --decorate --oneline --show-signature' # Check commit verification git log --show-signature -10 # Export audit log git log --pretty=format:"%H,%an,%ae,%ad,%s" --date=iso > git-audit.csv # Verify all commits in branch git log --show-signature main..HEAD
Security Checklist
Repository Setup:
- ☑ Enable branch protection
- ☑ Require signed commits
- ☑ Enable secret scanning with push protection
- ☑ Enable CodeQL or similar scanning
- ☑ Configure Dependabot/Renovate
- ☑ Require 2FA for all contributors
Developer Workstation:
- ☑ Use GPG or SSH commit signing
- ☑ Configure credential manager (never plaintext)
- ☑ Install and configure gitleaks
- ☑ Create comprehensive .gitignore
- ☑ Enable fsckobjects for transfers
- ☑ Use SSH keys with passphrase
Workflow:
- ☑ Never commit secrets
- ☑ Review changes before commit
- ☑ Verify signatures on pull/merge
- ☑ Regular security audits
- ☑ Rotate credentials periodically
- ☑ Use environment variables for secrets
Incident Response
Secret leaked in commit:
# 1. Rotate compromised credentials IMMEDIATELY # 2. Remove from latest commit (if not pushed) git reset HEAD~1 # Edit files to remove secret git add . git commit -m "Remove secrets" # 3. If pushed, remove from history git filter-repo --path config/secrets.yml --invert-paths git push --force # 4. Notify team to re-clone # 5. Enable push protection to prevent future leaks
Unsigned commits detected:
# Identify unsigned commits git log --show-signature | grep "No signature" # Re-sign commits (if you authored them) git rebase --exec 'git commit --amend --no-edit -n -S' -i HEAD~10 # Force push (with team coordination) git push --force-with-lease