Security Review Report - Convert to Markdown API

Generated: 2025-01-25 15:45 UTC
Status: Complete
Verified:

Executive Summary

This document presents a comprehensive security review of the Convert to Markdown API codebase. The review identified several security concerns ranging from minor information disclosure to potential credential exposure. While the application follows many security best practices, there are areas that require immediate attention to enhance the overall security posture.

Review Scope

The security review covered the following components:

1. Email Service Configuration (email-gmail-api.js)
2. Environment Configuration (.env files)
3. Test Scripts (test-email-config.js, test-signup-local.js)
4. Authentication Middleware (middleware/auth.js)
5. Input Validation (middleware/fileUpload.js)
6. API Endpoints (index.js)

Key Findings

1. Hard-coded Service Account Client ID

Severity: Medium
Location: functions/lib/email-gmail-api.js:102

The Gmail service account client ID is hard-coded in the error handling section:

console.error('Client ID should be: 116940581280353324169');

Risk: This exposes internal configuration details that could aid attackers in understanding the system architecture.

2. Email Address Exposure

Severity: Low
Location: Multiple files

The sender email address lindsay@knowcode.tech is hard-coded in several places:

• email-gmail-api.js:49
• .env files

Risk: While not critical, this creates maintenance issues and potential information disclosure.

3. Service Account Key Path Reference

Severity: Medium
Location: .env files, email configuration

The service account key path is referenced in environment variables:

GOOGLE_APPLICATION_CREDENTIALS=../deploy-gcp/keys/gmail-service-account.json

Risk: Path traversal and predictable file locations could be exploited if other vulnerabilities exist.

4. Test Files with Production-like Code

Severity: Low
Location: test-email-config.js, test-signup-local.js

Test files contain production-like code without proper isolation or mock implementations.

Risk: Accidental execution in production or exposure of test infrastructure.

5. Authentication Implementation

Severity: Well Implemented
Location: middleware/auth.js

Positive findings:

• Proper API key validation
• Rate limiting based on user plan
• Firestore integration for key management
• Good error handling with appropriate HTTP status codes

6. Input Validation

Severity: Well Implemented
Location: middleware/fileUpload.js

Positive findings:

• File size limits enforced (10MB)
• Proper MIME type handling
• Stream-based processing to prevent memory exhaustion
• Field name validation

7. Missing Security Headers

Severity: Medium
Location: API responses

The application does not set common security headers such as:

• X-Content-Type-Options
• X-Frame-Options
• X-XSS-Protection
• Strict-Transport-Security
• Content-Security-Policy

8. Verbose Error Messages

Severity: Low
Location: Throughout the application

Error messages sometimes reveal internal implementation details that could aid attackers.

Remediation Plan

Immediate Actions (High Priority)

1. Remove Hard-coded Client ID

   • Move the client ID to environment variables
   • Update error messages to be generic
   • Timeline: 1 day

2. Implement Security Headers

   • Add helmet.js or manually set security headers
   • Configure appropriate CSP policies
   • Timeline: 2 days

3. Secure Service Account Management

   • Use Google Secret Manager for service account keys
   • Remove file-based key storage
   • Timeline: 3 days

Short-term Actions (Medium Priority)

4. Environment Variable Management

   • Centralize all configuration in environment variables
   • Remove hard-coded email addresses
   • Use different configurations for dev/staging/prod
   • Timeline: 1 week

5. Error Message Sanitization

   • Implement a centralized error handler
   • Log detailed errors server-side
   • Return generic messages to clients
   • Timeline: 1 week

6. Test File Isolation

   • Move test files to a separate test directory
   • Use proper mocking for external services
   • Add .gitignore rules for test artifacts
   • Timeline: 3 days

Long-term Actions (Low Priority)

7. API Key Rotation

   • Implement automated key rotation
   • Add key expiration policies
   • Timeline: 2 weeks

8. Security Monitoring

   • Implement request anomaly detection
   • Add security event logging
   • Set up alerting for suspicious activities
   • Timeline: 3 weeks

9. Input Validation Enhancement

   • Add content scanning for uploaded files
   • Implement virus scanning integration
   • Timeline: 1 month

Security Best Practices Already Implemented

1. Authentication & Authorization

   • API key-based authentication
   • Rate limiting per user plan
   • Proper session management

2. Input Validation

   • File size limits
   • MIME type validation
   • Field validation

3. Error Handling

   • Structured error responses
   • Appropriate HTTP status codes
   • No stack traces in production

4. Data Protection

   • No persistent storage of user files
   • In-memory processing only
   • Automatic cleanup

Recommendations

1. Security Testing

   • Implement automated security scanning in CI/CD
   • Regular dependency vulnerability scanning
   • Penetration testing before major releases

2. Documentation

   • Create security guidelines for developers
   • Document security architecture
   • Maintain security incident response plan

3. Compliance

   • Review GDPR compliance for EU users
   • Implement data retention policies
   • Add security policy endpoints

Conclusion

The Convert to Markdown API demonstrates good security practices in authentication and input validation. However, the identified issues with hard-coded credentials, missing security headers, and service account management require immediate attention. Implementing the remediation plan will significantly improve the security posture of the application.

The development team should prioritize the immediate actions and establish a regular security review process to maintain and improve security over time.