{
  "ruleId": "S005",
  "name": "No Origin Header Authentication",
  "description": "Prevent using Origin header for authentication or authorization decisions",
  "category": "security",
  "severity": "error",
  "languages": ["typescript", "javascript"],
  "tags": ["security", "owasp", "authentication", "authorization", "spoofing", "headers"],
  "enabled": true,
  "fixable": false,
  "engine": "heuristic",
  "metadata": {
    "owaspCategory": "A07:2021 - Identification and Authentication Failures",
    "cweId": "CWE-290",
    "description": "Origin header can be easily spoofed by attackers and should not be used for authentication or authorization decisions. Use verified tokens, sessions, or cryptographic signatures instead.",
    "impact": "High - Authentication bypass, unauthorized access",
    "likelihood": "Medium",
    "remediation": "Use secure authentication methods: JWT tokens, session cookies, API keys with cryptographic signatures. Origin header should only be used for CORS/CSRF protection, not for access control."
  },
  "patterns": {
    "vulnerable": [
      "if (req.headers.origin === 'trusted.com') { authenticate() }",
      "const isAuthorized = allowedOrigins.includes(origin)",
      "if (origin.includes('admin')) { grantAccess() }",
      "switch(origin) { case 'internal': allow() }"
    ],
    "secure": [
      "Use for CORS: res.setHeader('Access-Control-Allow-Origin', origin)",
      "Use for CSRF: if (allowedOrigins.includes(origin)) { /* CSRF check */ }",
      "Use verified tokens: const user = await verifyJWT(req.headers.authorization)",
      "Use sessions: const user = await getSessionUser(req.session.id)"
    ]
  },
  "examples": {
    "violations": [
      "if (req.headers.origin === 'admin.example.com') { req.user = adminUser; }",
      "const hasAccess = trustedOrigins.includes(req.get('origin'))",
      "if (origin.endsWith('.internal.com')) { bypassAuth() }"
    ],
    "fixes": [
      "const user = await verifyToken(req.headers.authorization)",
      "const session = await validateSession(req.cookies.sessionId)",
      "const apiKey = await verifyApiKey(req.headers['x-api-key'])"
    ]
  }
}