GHSA-6fc8-4gx4-v693

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GHSA-6fc8-4gx4-v693

Summary: ReDoS in Sec-Websocket-Protocol header

Details: ### Impact A specially crafted value of the `Sec-Websocket-Protocol` header can be used to significantly slow down a ws server. ### Proof of concept ```js 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`](https://nodejs.org/api/cli.html#cli_max_http_header_size_size) and/or the [`maxHeaderSize`](https://nodejs.org/api/http.html#http_http_createserver_options_requestlistener) options. ### Credits The vulnerability was responsibly disclosed along with a fix in private by [Robert McLaughlin](https://github.com/robmcl4) from University of California, Santa Barbara.

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/issues/1895, https://github.com/websockets/ws/commit/00c425ec77993773d823f018f64a5c44e17023ff, https://github.com/websockets/ws, https://lists.apache.org/thread.html/rdfa7b6253c4d6271e31566ecd5f30b7ce1b8fb2c89d52b8c4e0f4e30@%3Ccommits.tinkerpop.apache.org%3E, https://security.netapp.com/advisory/ntap-20210706-0005