dcyfr-security

What I do

I guide security practices and CodeQL false positive suppression:

• CodeQL suppressions with LGTM syntax
• Security vulnerability troubleshooting (SSRF, CWE-918)
• False positive patterns and verification
• Security testing patterns

When to use me

✅ Use this skill when:

• Suppressing CodeQL false positives
• Investigating security alerts
• Implementing security fixes
• Reviewing security-sensitive code

❌ Don't use this skill for:

• General code review (use dcyfr-validation)
• Performance issues (separate concern)
• Non-security bugs

CodeQL Suppression Syntax

Basic Suppression

// lgtm[js/path-injection]
const filePath = path.join(baseDir, userInput);

With Justification

// lgtm[js/sql-injection]: Input validated by schema
const query = `SELECT * FROM users WHERE id = ${userId}`;

Multiple Alerts

// lgtm[js/path-injection,js/sql-injection]
const result = await processInput(userInput);

Common False Positives

1. Path Injection (Safe)

// lgtm[js/path-injection]: userInput validated against allowlist
const filePath = path.join(PUBLIC_DIR, userInput);

2. SQL Injection (Parameterized)

// lgtm[js/sql-injection]: Using parameterized query
await db.query('SELECT * FROM users WHERE id = $1', [userId]);

3. XSS (React Auto-Escapes)

// lgtm[js/xss]: React auto-escapes JSX content
<div>{userContent}</div>

Security Testing Patterns

API Endpoint Security Test

describe('/api/secure-endpoint', () => {
  it('rejects unauthorized requests', async () => {
    const response = await fetch('/api/secure-endpoint');
    expect(response.status).toBe(401);
  });

  it('validates input', async () => {
    const response = await fetch('/api/secure-endpoint', {
      method: 'POST',
      body: JSON.stringify({ malicious: '<script>alert(1)</script>' }),
    });
    expect(response.status).toBe(400);
  });
});

SSRF Prevention

// ✅ CORRECT: Validate URLs before fetching
const allowedDomains = ['api.trusted.com'];
const url = new URL(userProvidedUrl);

if (!allowedDomains.includes(url.hostname)) {
  throw new Error('Invalid domain');
}

const response = await fetch(url.toString());

Related Documentation

• CodeQL suppressions: .github/agents/patterns/CODEQL_SUPPRESSIONS.md
• Security troubleshooting: .github/agents/patterns/SECURITY_VULNERABILITY_TROUBLESHOOTING.md

Approval Gates

Security compliance is STRICT (hard block):

• ❌ Cannot suppress without justification
• ❌ Cannot merge with HIGH/CRITICAL alerts
• ✅ Must verify suppressions are valid