Regular Expression Denial of Service (ReDoS)
Affecting ms package, versions <2.0.0
ms is a tiny milisecond conversion utility.
Affected versions of this package are vulnerable to Regular Expression Denial of Service (ReDoS) due to an incomplete fix for previously reported vulnerability npm:ms:20151024. The fix limited the length of accepted input string to 10,000 characters, and turned to be insufficient making it possible to block the event loop for 0.3 seconds (on a typical laptop) with a specially crafted string passed to
Proof of concept
ms = require('ms'); ms('1'.repeat(9998) + 'Q') // Takes about ~0.3s
Note: Snyk's patch for this vulnerability limits input length to 100 characters. This new limit was deemed to be a breaking change by the author. Based on user feedback, we believe the risk of breakage is very low, while the value to your security is much greater, and therefore opted to still capture this change in a patch for earlier versions as well. Whenever patching security issues, we always suggest to run tests on your code to validate that nothing has been broken.
For more information on
Regular Expression Denial of Service (ReDoS) attacks, go to our blog.
- Feb 9th, 2017 - Reported the issue to package owner.
- Feb 11th, 2017 - Issue acknowledged by package owner.
- April 12th, 2017 - Fix PR opened by Snyk Security Team.
- May 15th, 2017 - Vulnerability published.
- May 16th, 2017 - Issue fixed and version
- May 21th, 2017 - Patches released for versions
ms to version 2.0.0 or higher.
Snyk patch available for versions:
Do your applications use this vulnerable package?
- Snyk Security Research Team
- Snyk ID
- 11 Apr, 2017
- 15 May, 2017