Timing Attack Affecting fernet package, versions <0.1.0 >=0.0.1
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Test your applications- Snyk ID npm:fernet:20140306
- published 22 Nov 2016
- disclosed 6 Mar 2014
- credit Chris Continanza
How to fix?
Upgrade fernet to version 0.1.0 or higher.
Overview
fernet is a Javascript implementation of Fernet symmetric encryption.
Affected versions of the package are vulnerable to a timing attack.
The library implemented a character to character comparison, similar to 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 HMAC are incorrect.
An attacker can use this difference to perform a timing attack, essentially allowing them to guess the HMAC one character at a time.
You can read more about timing attacks in Node.js on the Snyk blog.