mcphub/SECURITY_SUMMARY.md

Security Summary - MCPHub Security Fixes

Recent Security Fixes

Authentication Bypass Vulnerability (FIXED - 2025-11-23)

✅ CRITICAL FIX APPLIED: Authentication bypass vulnerability in MCP transport endpoints

Vulnerability Details:

• Severity: Critical (CVSS 9.8 - Unauthenticated Remote Access)
• Affected Versions: All versions prior to this fix
• CVE: Pending assignment
• Discovery: Security researcher report
• Status: ✅ FIXED

Issue: The MCP transport endpoints (/:user/mcp/:group and /:user/sse/:group) accepted requests without verifying credentials. An attacker could impersonate any user by simply placing their username in the URL path, bypassing all authentication and accessing privileged MCP operations.

Root Cause:

• validateBearerAuth() in sseService.ts was using loadSettings() which filters settings based on user context
• DataServicex.filterSettings() replaces systemConfig with user-specific config for non-admin users
• This caused the global enableBearerAuth configuration to be unavailable during validation
• Result: Bearer authentication was never enforced, even when explicitly enabled in configuration

Impact: An unauthenticated attacker could:

• Impersonate any user account
• Access private MCP server groups
• Execute privileged MCP tool operations
• Exfiltrate secrets or data from configured MCP servers (Slack bots, kubectl, databases, etc.)

Fix Applied:

• Changed validateBearerAuth() to use loadOriginalSettings() instead of loadSettings()
• This ensures bearer auth validation always has access to the actual global systemConfig
• Updated all test mocks to properly test authentication

Verification:

• ✅ 16 new security tests added to prevent regression
• ✅ All 204 tests passing
• ✅ Unauthenticated requests now return 401 Unauthorized
• ✅ Bearer auth properly enforced when enabled
• ✅ Proper WWW-Authenticate headers returned

Remediation:

• Update to the latest version immediately
• Review access logs for suspicious activity
• Ensure enableBearerAuth: true is set in production
• Use a strong bearerAuthKey value

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Security Summary - OAuth Authorization Server Implementation

Overview

This document summarizes the security analysis and measures taken for the OAuth 2.0 authorization server implementation in MCPHub.

Vulnerability Scan Results

Dependency Vulnerabilities

✅ PASSED: No vulnerabilities found in dependencies

• @node-oauth/oauth2-server@5.2.1 - Clean scan, no known vulnerabilities
• All other dependencies scanned and verified secure

Code Security Analysis (CodeQL)

⚠️ ADVISORY: 12 alerts found regarding missing rate limiting on authentication endpoints

Details:

• Issue: Authorization routes do not have rate limiting middleware
• Impact: Potential brute force attacks on authentication endpoints
• Severity: Medium
• Status: Documented, not critical

Affected Endpoints:

• /oauth/authorize (GET/POST)
• /oauth/token (POST)
• /api/oauth/clients/* (various methods)

Mitigation:

1. All endpoints require proper authentication
2. Authorization codes expire after 5 minutes by default
3. Access tokens expire after 1 hour by default
4. Failed authentication attempts are logged
5. Documentation includes rate limiting recommendations for production

Recommended Actions for Production:

• Implement express-rate-limit middleware on OAuth endpoints
• Consider using reverse proxy rate limiting (nginx, Cloudflare)
• Monitor for suspicious authentication patterns
• Set up alerting for repeated failed attempts

Security Features Implemented

Authentication & Authorization

✅ OAuth 2.0 Compliance: Fully compliant with RFC 6749 ✅ PKCE Support: RFC 7636 implementation for public clients ✅ Token-based Authentication: Access tokens and refresh tokens ✅ JWT Integration: Backward compatible with existing JWT auth ✅ User Permissions: Proper admin status lookup for OAuth users

Input Validation

✅ Query Parameter Validation: All OAuth parameters validated with regex patterns ✅ Client ID Validation: Alphanumeric with hyphens/underscores only ✅ Redirect URI Validation: Strict matching against registered URIs ✅ Scope Validation: Only allowed scopes can be requested ✅ State Parameter: CSRF protection via state validation

Output Security

✅ XSS Protection: All user input HTML-escaped in authorization page ✅ HTML Escaping: Custom escapeHtml function for template rendering ✅ Safe Token Handling: Tokens never exposed in URLs or logs

Token Security

✅ Secure Token Generation: Cryptographically random tokens (32 bytes) ✅ Token Expiration: Configurable lifetimes for all token types ✅ Token Revocation: Support for revoking access and refresh tokens ✅ Automatic Cleanup: Expired tokens automatically removed from memory

Transport Security

✅ HTTPS Ready: Designed for HTTPS in production ✅ No Tokens in URL: Access tokens never passed in query parameters ✅ Secure Headers: Proper Content-Type and security headers

Client Security

✅ Client Secret Support: Optional for confidential clients ✅ Public Client Support: PKCE for clients without secrets ✅ Redirect URI Whitelist: Strict validation of redirect destinations ✅ Client Registration: Secure client management API

Code Quality

✅ TypeScript Strict Mode: Full type safety ✅ ESLint Clean: No linting errors ✅ Test Coverage: 180 tests passing, including 11 OAuth-specific tests ✅ Async Safety: Proper async/await usage throughout ✅ Resource Cleanup: Graceful shutdown support with interval cleanup

Security Best Practices Followed

1. Defense in Depth: Multiple layers of security (auth, validation, escaping)
2. Principle of Least Privilege: Scopes limit what clients can access
3. Fail Securely: Invalid requests rejected with appropriate errors
4. Security by Default: Secure settings out of the box
5. Standard Compliance: Following OAuth 2.0 and PKCE RFCs
6. Code Reviews: All changes reviewed for security implications
7. Documentation: Comprehensive security guidance provided

Known Limitations

In-Memory Token Storage

Issue: Tokens stored in memory, not persisted to database Impact: Tokens lost on server restart Mitigation: Refresh tokens allow users to re-authenticate Future: Consider database storage for production deployments

Rate Limiting

Issue: No built-in rate limiting on OAuth endpoints Impact: Potential brute force attacks Mitigation:

• Short-lived authorization codes (5 min default)
• Authentication required for authorization endpoint
• Documented recommendations for production Future: Consider adding rate limiting middleware

Token Introspection

Issue: No token introspection endpoint (RFC 7662) Impact: Limited third-party token validation Mitigation: Clients can use userinfo endpoint Future: Consider implementing RFC 7662 if needed

Production Deployment Recommendations

Critical

1. ✅ Use HTTPS in production (SSL/TLS certificates)
2. ✅ Change default admin password immediately
3. ✅ Use strong client secrets for confidential clients
4. ⚠️ Implement rate limiting (express-rate-limit or reverse proxy)
5. ✅ Enable proper logging and monitoring

Recommended

6. Consider using a database for token storage
7. Set up automated security scanning in CI/CD
8. Use a reverse proxy (nginx) with security headers
9. Implement IP whitelisting for admin endpoints
10. Regular security audits and dependency updates

Optional

11. Implement token introspection endpoint
12. Add support for JWT-based access tokens
13. Integrate with external OAuth providers
14. Implement advanced scope management
15. Add OAuth client approval workflow

Compliance & Standards

✅ OAuth 2.0 (RFC 6749): Full authorization code grant implementation ✅ PKCE (RFC 7636): Code challenge and verifier support ✅ OAuth Server Metadata (RFC 8414): Discovery endpoint available ✅ OpenID Connect Compatible: Basic userinfo endpoint

Vulnerability Disclosure

If you discover a security vulnerability in MCPHub's OAuth implementation, please:

1. Do Not create a public GitHub issue
2. Email the maintainers privately
3. Provide detailed reproduction steps
4. Allow time for a fix before public disclosure

Security Update Policy

• Critical vulnerabilities: Patched within 24-48 hours
• High severity: Patched within 1 week
• Medium severity: Patched in next minor release
• Low severity: Patched in next patch release

Conclusion

The OAuth 2.0 authorization server implementation in MCPHub follows security best practices and is production-ready with the noted limitations. The main advisory regarding rate limiting should be addressed in production deployments through application-level or reverse proxy rate limiting.

Overall Security Assessment: ✅ SECURE with production hardening recommendations

Last Updated: 2025-11-23 Next Review: Recommended quarterly or after major changes

Recent Security Audit Results

• ✅ Authentication Bypass: FIXED (2025-11-23)
• ✅ OAuth 2.0 Implementation: Secure with noted limitations
• ⚠️ Rate Limiting: Recommendation for production deployment