🛡️ Sentinel: [HIGH] Fix timing attack in token authentication#282
🛡️ Sentinel: [HIGH] Fix timing attack in token authentication#282google-labs-jules[bot] wants to merge 1 commit into
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The previous implementation of token authentication in `src/cli/commands/serve.ts` short-circuited constant-time comparison if the lengths of the provided token and expected token did not match. This allowed attackers to infer the length of a token via a timing side channel. This fix hashes both the provided and expected tokens to a fixed length using SHA-256 prior to calling `crypto.timingSafeEqual`, ensuring a true constant-time comparison.
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🚨 Severity: HIGH
💡 Vulnerability: Fast-path short-circuiting in token validation using buffer length comparisons before calling
crypto.timingSafeEqualintroduced a timing attack vulnerability, leaking the length of the secret token.🎯 Impact: Attackers could deduce the length of the authentication token, significantly reducing the complexity of brute-force attacks.
🔧 Fix: Modified the authentication logic to hash both the expected and provided tokens to a fixed length (using SHA-256) before performing the constant-time comparison, eliminating the length check.
✅ Verification: Ensure the test suite passes and that authentication logic does not short-circuit based on input length.
PR created automatically by Jules for task 8549029983029992682 started by @YoungSx