Non-Constant Time String Comparison Affecting csrf-lite Open this link in a new tab package, versions <=0.1.1

  • Attack Complexity


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  • snyk-id


  • published

    22 Jun 2016

  • disclosed

    23 Apr 2016

  • credit

    Todd Wolfson

How to fix?

Update to version 0.1.2 or higher.


csrf-lite is a CSRF protection utility for framework-free node sites. Affected versions of the package are vulnerable to a timing attack.

While the CSRF protection itself works well and increases security, the library uses the built-in string comparison mechanism, ===, and not a time constant string comparison. As a result, the comparison will fail faster when the first characters in the token are incorrect. An attacker can use this difference to perform a timing attack, essentially allowing them to guess the CSRF token one character at a time.

You can read more about timing attacks in Node.js on the Snyk blog: