Security: password gate uses non-constant-time comparison, vulnerable to timing attacks

[Sertug17]

Summary

app/api/gate/route.ts compares the submitted password against SITE_PASSWORD using a plain !== string comparison. JavaScript string comparison short-circuits on the first mismatched character, meaning the operation takes slightly longer when more leading characters are correct.

Impact

An attacker with network access to /api/gate can send many requests with varying passwords and measure response latency. By observing which prefixes produce longer responses, they can converge on the correct password one character at a time reducing a brute-force search from exponential to linear.

Root cause

// app/api/gate/route.ts
if (provided !== password) {   // ← timing-sensitive

Fix

Replace with timingSafeEqual from node:crypto, which always takes constant time regardless of where the buffers differ:

const providedBuf = Buffer.from(provided);
const passwordBuf = Buffer.from(password);
const match =
  providedBuf.length === passwordBuf.length &&
  timingSafeEqual(providedBuf, passwordBuf);

References

• Node.js crypto.timingSafeEqual
• CWE-208: Observable Timing Discrepancy