tomevault-io Static Site Security Skill
Purpose
Comprehensive security practices for static websites, leveraging their inherent security advantages while addressing remaining risks.
Security Advantages of Static Sites
Eliminated Attack Vectors
✅ No SQL Injection: No database to inject into ✅ No Server-Side XSS: No server-side rendering ✅ No CSRF: No state management or forms processing ✅ No Session Hijacking: No sessions to hijack ✅ No Remote Code Execution: No server-side code ✅ No File Upload Vulnerabilities: No upload functionality ✅ No Authentication Bypass: No authentication system
Reduced Attack Surface
Traditional Web App Attack Surface:
- Web server vulnerabilities
- Application code vulnerabilities
- Database vulnerabilities
- Server OS vulnerabilities
- Third-party libraries
- Session management
- File system access
- Network services
Static Site Attack Surface:
- CDN security (GitHub Pages)
- DNS hijacking
- Content integrity
- Dependency vulnerabilities (minimal)
Transport Layer Security
HTTPS Configuration
✅ Required:
- HTTPS-only (TLS 1.3)
- Automatic HTTPS redirect
- Valid SSL/TLS certificate
- Perfect Forward Secrecy (PFS)
For GitHub Pages:
- Enforced HTTPS in repository settings
- Automatic Let's Encrypt certificates
- TLS 1.3 support by default
Security Headers
Essential headers for static sites:
Content-Security-Policy:
default-src 'self';
script-src 'self';
style-src 'self' 'unsafe-inline' fonts.googleapis.com;
font-src 'self' fonts.gstatic.com;
img-src 'self' data:;
connect-src 'self';
frame-ancestors 'none';
Strict-Transport-Security:
max-age=31536000; includeSubDomains; preload
X-Content-Type-Options:
nosniff
X-Frame-Options:
DENY
Referrer-Policy:
strict-origin-when-cross-origin
Permissions-Policy:
geolocation=(), microphone=(), camera=()
Content Security
Subresource Integrity (SRI)
<!-- ✅ Good: SRI for stable, versioned external resources -->
<script
src="https://cdn.example.com/script.v1.2.3.js"
integrity="sha384-..."
crossorigin="anonymous"
></script>
<!-- ⚠️ Google Fonts: dynamic content, SRI not reliable unless you self-host -->
<!-- Either self-host the font CSS with SRI, or omit SRI for the dynamic URL: -->
<link
rel="stylesheet"
href="https://fonts.googleapis.com/css2?family=Inter"
crossorigin="anonymous"
>
<!-- ❌ Bad: No integrity check on a static, versioned asset -->
<script src="https://cdn.example.com/script.v1.2.3.js"></script>
Dependency Management
✅ Best practices:
1. Minimize external dependencies
2. Use trusted CDNs only (Google Fonts, etc.)
3. Implement SRI for CDN resources
4. Regular dependency scanning
5. Prefer self-hosted over CDN when possible
6. Document all external dependencies
HTML Injection Prevention
<!-- Even static sites can have issues if using templates -->
<!-- ❌ Bad: Unsafe data in HTML -->
<div>{{ userData }}</div>
<!-- ✅ Good: Escaped/sanitized -->
<div>{{ userData | escape }}</div>
<!-- ✅ Best: Static content only -->
<div>Hardcoded safe content</div>
Access Control Security
GitHub Repository Security
✅ Required access controls:
- MFA enabled for all contributors
- SSH keys with passphrase
- GPG commit signing required
- Branch protection on main/master
- Required pull request reviews
- Status checks must pass
- Restrict who can push
- Restrict force pushes
GitHub Pages Security
✅ Configuration:
- Enforce HTTPS enabled
- Source branch restricted (main only)
- Custom domain with DNSSEC (optional)
- Repository visibility: Public (for open source)
Secrets Management
✅ Never commit:
- API keys
- Passwords
- Private keys
- OAuth tokens
- Any credentials
✅ Use instead:
- GitHub Secrets for CI/CD
- Environment variables
- Secure credential stores
- GitHub Apps (not PATs when possible)
CDN and Hosting Security
GitHub Pages Security Model
✅ GitHub provides:
- Global CDN with DDoS protection
- Automatic TLS certificates
- High availability (99.9% SLA)
- Infrastructure security
- Regular security updates
⚠️ User responsibilities:
- Content security
- Access control
- Dependency management
- Security monitoring
DNS Security
✅ Best practices:
- Use DNSSEC if supported
- CAA records for certificate authority
- Monitor DNS for hijacking
- Use reputable DNS provider
Example CAA record:
example.com. CAA 0 issue "letsencrypt.org"
Monitoring and Detection
Security Monitoring
✅ Implement monitoring for:
- GitHub security alerts
- Dependabot vulnerability alerts
- Secret scanning alerts
- Code scanning (CodeQL) alerts
- Unusual access patterns
- Repository changes
- Workflow failures
Audit Logging
✅ Enable and review:
- GitHub audit log (organization)
- GitHub Actions logs
- Commit history (immutable)
- Access logs (GitHub provides)
- Security event logs
Alerting Strategy
Critical alerts (immediate response):
- Secret exposure detected
- Unauthorized access attempt
- Critical vulnerability found
- Security workflow failure
Warning alerts (24h response):
- Dependency with high severity CVE
- Failed security checks
- Unusual activity patterns
Info alerts (weekly review):
- New dependencies added
- Configuration changes
- Access changes
Incident Response
Detection
1. Automated alerts (Dependabot, CodeQL, secret scanning)
2. Manual monitoring (code reviews, security audits)
3. External reports (responsible disclosure)
4. GitHub security advisories
Containment
Immediate actions:
1. Disable GitHub Pages if compromised
2. Revoke exposed credentials
3. Block malicious IP addresses (if applicable)
4. Revert to last known good state
Recovery
Steps:
1. Identify root cause
2. Fix vulnerability
3. Test fix thoroughly
4. Deploy patched version
5. Verify security restored
6. Monitor for recurrence
Post-Incident
Actions:
1. Document incident timeline
2. Update THREAT_MODEL.md
3. Update SECURITY_ARCHITECTURE.md
4. Improve detection capabilities
5. Share lessons learned
6. Update incident response procedures
Deployment Security
CI/CD Security
# Security-hardened deployment workflow
name: Deploy
on:
push:
branches: [main]
permissions:
contents: read # Least privilege
jobs:
deploy:
runs-on: ubuntu-latest
steps:
- uses: step-security/harden-runner@SHA
with:
egress-policy: audit
- uses: actions/checkout@SHA
- name: Security Scan
run: |
# HTML validation
htmlhint *.html
# Link check
linkinator . --recurse
# Dependency check
npm audit
- name: Deploy
if: success()
run: echo "Deploy to GitHub Pages"
Rollback Procedures
✅ Ensure capability to:
1. Revert to previous commit (git revert)
2. Redeploy last known good version
3. Disable site temporarily if needed
4. Restore from backup if necessary
RTO (Recovery Time Objective): < 15 minutes
RPO (Recovery Point Objective): Last commit
Security Testing
Pre-Deployment Tests
Automated tests:
- HTML validation (HTMLHint)
- Link checking (linkinator)
- Dependency scanning (Dependabot)
- Secret scanning (GitHub)
- Code scanning (CodeQL)
Manual tests:
- Security header verification
- HTTPS enforcement check
- Content review
- Access control verification
Security Audit Checklist
Monthly audit:
- [ ] Review GitHub security alerts
- [ ] Check for exposed secrets
- [ ] Verify HTTPS enforcement
- [ ] Test security headers
- [ ] Review access controls
- [ ] Update dependencies
- [ ] Review commit history
- [ ] Test rollback procedures
Quarterly audit:
- [ ] Full threat model review
- [ ] Penetration testing (if applicable)
- [ ] Security architecture review
- [ ] Incident response drill
- [ ] Third-party security assessment
Remember
- Leverage Static Advantages: No server-side code = no server-side vulnerabilities
- Transport Security: Always HTTPS with strong headers
- Minimize Dependencies: Each dependency is potential risk
- Monitor Continuously: Automated scanning catches issues early
- Access Control: Protect the source, protect the site
- Plan for Incidents: Detection, response, recovery procedures
- Document Everything: Security decisions and configurations
References
- OWASP Static Site Security
- GitHub Pages Documentation
- Mozilla Web Security Guidelines
- Content Security Policy
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