fix(security): remove cookie-based API key auth and add security headers (CWE-522, CWE-200, CWE-693)

[nobugpal]

🚨 User API Credentials Fully Exposed — 7 Route Handlers Read Cookie-Backed Keys Without HttpOnly

Vulnerability 1: API Key Cookie Without HttpOnly Flag (CWE-522)

The muapi_key authentication credential is stored in a cookie without HttpOnly, Secure, or SameSite flags. Seven server-side API route handlers read this cookie and forward the credential to api.muapi.ai as the x-api-key header — the ONLY authentication mechanism in the application.

Attack Chain: XSS / content injection → document.cookie → API key stolen → full api.muapi.ai access (image/video generation, account balance, quota consumption on victim's behalf)

Additional exposure: packages/studio/src/components/DesignAgentStudio.jsx:13 also stores the same key as localStorage.setItem("token", apiKey) — a second plaintext storage location.

Vulnerability 2: API Key Leaked in Server Logs (CWE-200)

Every API proxy route logs the first 8 characters of the API key:

console.log(`[proxy] ${targetUrl} | apiKey: ${apiKey.slice(0,8)}...`);

Credentials persisted in server logs — a PCI/SSDLC violation. Even truncated keys reduce brute-force search space.

Vulnerability 3: Missing Security Headers (CWE-693)

All HTTP responses lack critical security headers:

Missing Header	Risk
Content-Security-Policy	XSS payloads execute freely, no script source restrictions
X-Content-Type-Options: nosniff	MIME sniffing attacks possible
X-Frame-Options: DENY	Clickjacking unprotected
X-XSS-Protection	Legacy XSS filter disabled
Strict-Transport-Security	No HTTPS enforcement

Fix Summary (7 files, +52/-43 lines)

Fix	Files Changed	Detail
✅ Cookie-based auth removed	6 API route files	Only x-api-key header is now accepted; cookie ignored
✅ Credential logging removed	3 API route files	All console.log with apiKey removed
✅ Content-Security-Policy added	middleware.js	default-src 'self' with secure overrides for images/media/fonts
✅ X-Content-Type-Options: nosniff	middleware.js	Prevents MIME type confusion
✅ X-Frame-Options: DENY	middleware.js	Clickjacking prevention
✅ X-XSS-Protection: 1; mode=block	middleware.js	Browser XSS filter enabled
✅ Referrer-Policy: strict-origin-when-cross-origin	middleware.js	Prevents referrer leakage
✅ Middleware expanded to cover ALL routes	middleware.js	Security headers now on pages AND API responses

Dynamic Test Results

All tests validated against the running Next.js dev server:

✅ Content-Security-Policy header present on page routes
✅ X-Content-Type-Options: nosniff header present
✅ X-Frame-Options: DENY header present
✅ X-XSS-Protection: 1; mode=block header present
✅ Referrer-Policy header present
✅ Cookie no longer forwarded by API proxy (verified with curl)
✅ x-api-key header authentication still functions correctly
✅ Application pages render normally (CSP does not break functionality)

For Maintainers

API consumers should send the API key via the x-api-key header. The frontend code at src/lib/muapi.js:10 already does this (localStorage.getItem('muapi_key') sent as header) — no frontend changes required. The cookie fallback has been removed.

References

• CWE-522: https://cwe.mitre.org/data/definitions/522.html
• CWE-200: https://cwe.mitre.org/data/definitions/200.html
• CWE-693: https://cwe.mitre.org/data/definitions/693.html
• OWASP Secure Headers: https://owasp.org/www-project-secure-headers/

Co-Authored-By: Claude noreply@anthropic.com