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


0.0
medium
  • Attack Complexity

    Low

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  • snyk-id

    npm:csrf-lite:20160423

  • published

    22 Jun 2016

  • disclosed

    23 Apr 2016

  • credit

    Todd Wolfson

How to fix?

Update to version 0.1.2 or higher.

Overview

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: https://snyk.io/blog/node-js-timing-attack-ccc-ctf/