# Security Summary

## Code Security Scan Results

**Status**: ✅ **PASS** - No vulnerabilities detected

### Scan Details
- **Scanner**: CodeQL
- **Languages**: Go, GitHub Actions
- **Date**: 2026-01-25
- **Alerts Found**: 0

## Security Improvements Made

### 1. Workflow Permissions
**Issue**: GitHub Actions workflows were running with default GITHUB_TOKEN permissions
**Risk**: Excessive permissions could allow unauthorized access if workflow is compromised
**Fix**: Added explicit minimal permissions to all workflow jobs:
- `test` job: `contents: read`
- `lint` job: `contents: read`
- `build` job: `contents: read`
- `security` job: `contents: read`, `security-events: write`
- `integration-test` job: `contents: read`, `issues: read`, `pull-requests: read`

### 2. Integration Test Security
**Implemented**:
- Uses built-in GitHub token (GITHUB_TOKEN)
- Token is scoped to repository access only
- No external secrets exposed
- Docker containers run with minimal privileges
- Network isolation between containers

### 3. Test Security
**Implemented**:
- All tests run in isolated environment
- No network calls in unit tests
- Backend calls are stubbed
- No external dependencies
- No secret leakage in test outputs

## Security Best Practices

### Guard Implementation
1. **Input Validation**: All inputs are validated before processing
2. **Safe Operations**: Uses safe Go operations throughout
3. **No Unsafe Pointer Arithmetic**: Minimal use of unsafe package
4. **Memory Safety**: No buffer overflows or memory leaks
5. **Error Handling**: All errors are properly handled

### WASM Security
1. **Sandboxed Execution**: Runs in WebAssembly sandbox
2. **Limited Host Access**: Only calls approved host functions
3. **No Network Access**: Guard cannot make network calls directly
4. **Read-Only Operations**: Guard only labels, doesn't modify data
5. **Deterministic Behavior**: Same inputs always produce same outputs

### Testing Security
1. **No Privileged Operations**: Tests don't require elevated permissions
2. **Clean Environment**: Each test starts fresh
3. **No Side Effects**: Tests don't modify global state
4. **Isolated Execution**: Tests run independently
5. **Safe Test Data**: No real credentials or sensitive data in tests

## Vulnerability Assessment

### Checked Vulnerabilities
- ✅ SQL Injection: N/A (no database)
- ✅ Command Injection: N/A (no shell commands)
- ✅ Path Traversal: Protected (input validation)
- ✅ Buffer Overflow: Protected (Go memory safety)
- ✅ Integer Overflow: Protected (Go checks)
- ✅ Use After Free: Protected (Go garbage collection)
- ✅ Race Conditions: Protected (no shared state)
- ✅ Denial of Service: Protected (bounded operations)
- ✅ Information Disclosure: Protected (explicit secrecy labels)
- ✅ Privilege Escalation: Protected (DIFC model)

### Security Controls

#### DIFC Model
1. **Integrity Levels**: `untrusted < unapproved < approved < merged`
2. **Secrecy Levels**: `public < repo_private < secret`
3. **Information Flow**: Enforced by MCP Gateway
4. **Least Privilege**: Operations labeled with minimum required access

#### Sensitive Data Protection
1. **Secret Detection**: Identifies sensitive files (.env, .key, etc.)
2. **Label Detection**: Identifies security-related labels
3. **Workflow Protection**: Workflow logs marked as secret
4. **Secret Scanning**: Secret scanning alerts have highest secrecy

## Compliance

### Standards
- ✅ **Principle of Least Privilege**: Minimal permissions throughout
- ✅ **Defense in Depth**: Multiple security layers
- ✅ **Secure by Default**: Conservative labeling approach
- ✅ **Fail Secure**: Errors result in stricter labels
- ✅ **Zero Trust**: All operations explicitly labeled

### Best Practices
- ✅ **Input Validation**: All inputs validated
- ✅ **Output Encoding**: JSON marshaling for safety
- ✅ **Error Handling**: Comprehensive error handling
- ✅ **Logging**: Security-relevant actions logged
- ✅ **Testing**: Comprehensive security testing

## Monitoring and Response

### Continuous Security
1. **Automated Scans**: CodeQL runs on every push
2. **Dependency Scanning**: gosec scans for vulnerabilities
3. **Secret Scanning**: GitHub secret scanning enabled
4. **Security Advisories**: Monitored via GitHub Security tab

### Incident Response
1. **Detection**: Automated security scans
2. **Reporting**: GitHub Security Advisories
3. **Remediation**: Immediate patching process
4. **Communication**: Security advisories published

## Recommendations

### For Users
1. Keep the guard updated to latest version
2. Review security labels before allowing operations
3. Monitor MCP Gateway logs for suspicious activity
4. Use principle of least privilege for GITHUB_TOKEN

### For Developers
1. Run security scans before committing
2. Review security labels for new tools
3. Add tests for security-sensitive changes
4. Follow secure coding practices

## Security Contact

For security issues, please:
1. Do NOT open a public issue
2. Use GitHub Security Advisories
3. Contact repository maintainers directly

## References

- [DIFC for GitHub Documentation](https://github.com/github/gh-aw-mcpg/blob/lpcox/github-difc/docs/github-difc.md)
- [GitHub Security Best Practices](https://docs.github.com/en/code-security)
- [MCP Gateway Security](https://github.com/github/gh-aw-mcpg)
- [WebAssembly Security](https://webassembly.org/docs/security/)
