🔒 [Fix Timing Attack Vulnerability in API Key Check]

[suranig]

🎯 What: Fixed a timing attack vulnerability in the API key comparison logic by implementing a secure timingSafeStringEqual utility.

⚠️ Risk: The previous use of the standard equality operator (===) allowed attackers to potentially guess the API key character-by-character by measuring small differences in response times. This could lead to unauthorized cache clearance or revalidation in production environments.

🛡️ Solution:

1. Implemented timingSafeStringEqual in src/instrumentation/index.ts. It hashes both inputs with SHA-256 before comparing them with crypto.timingSafeEqual. This approach is secure even for strings of different lengths and prevents timing leaks for both the value and the length of the secret.
2. Updated the JSDoc @example in src/instrumentation/index.ts to promote secure coding practices.
3. Updated the example API route examples/next-pages-router/api/revalidate.ts to use the secure comparison.
4. Added test/security.test.ts with comprehensive test cases (matching, mismatching, length mismatch, and invalid types).

Verification:

• Manually verified the logic with a Node.js script due to environment-specific network issues preventing full npm install.
• Verified matching strings return true.
• Verified mismatching strings (same and different lengths) return false.
• Verified non-string inputs are handled gracefully.

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PR created automatically by Jules for task 12089195514271818230 started by @suranig

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.

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