ghsa-6fc8-4gx4-v693
Vulnerability from github
Published
2021-05-28 19:19
Modified
2021-10-06 22:05
Severity ?
5.3 (Medium) - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
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 ws@7.4.6 (https://github.com/websockets/ws/commit/00c425ec77993773d823f018f64a5c44e17023ff) and backported to ws@6.2.2 (https://github.com/websockets/ws/commit/78c676d2a1acefbc05292e9f7ea0a9457704bf1b) and ws@5.2.3 (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.

Show details on source website

To clipboard 

{
  "affected": [
    {
      "package": {
        "ecosystem": "npm",
        "name": "ws"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "7.0.0"
            },
            {
              "fixed": "7.4.6"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "npm",
        "name": "ws"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "6.0.0"
            },
            {
              "fixed": "6.2.2"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "npm",
        "name": "ws"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "5.0.0"
            },
            {
              "fixed": "5.2.3"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2021-32640"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-345",
      "CWE-400"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2021-05-28T18:18:04Z",
    "nvd_published_at": "2021-05-25T19:15:00Z",
    "severity": "MODERATE"
  },
  "details": "### Impact\n\nA specially crafted value of the `Sec-Websocket-Protocol` header can be used to significantly slow down a ws server.\n\n### Proof of concept\n\n```js\nfor (const length of [1000, 2000, 4000, 8000, 16000, 32000]) {\n  const value = \u0027b\u0027 + \u0027 \u0027.repeat(length) + \u0027x\u0027;\n  const start = process.hrtime.bigint();\n\n  value.trim().split(/ *, */);\n\n  const end = process.hrtime.bigint();\n\n  console.log(\u0027length = %d, time = %f ns\u0027, length, end - start);\n}\n```\n\n### Patches\n\nThe vulnerability was fixed in ws@7.4.6 (https://github.com/websockets/ws/commit/00c425ec77993773d823f018f64a5c44e17023ff) and backported to ws@6.2.2 (https://github.com/websockets/ws/commit/78c676d2a1acefbc05292e9f7ea0a9457704bf1b) and ws@5.2.3 (https://github.com/websockets/ws/commit/76d47c1479002022a3e4357b3c9f0e23a68d4cd2).\n\n### Workarounds\n\nIn 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.\n\n### Credits\n\nThe vulnerability was responsibly disclosed along with a fix in private by [Robert McLaughlin](https://github.com/robmcl4) from University of California, Santa Barbara.\n",
  "id": "GHSA-6fc8-4gx4-v693",
  "modified": "2021-10-06T22:05:51Z",
  "published": "2021-05-28T19:19:03Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/websockets/ws/security/advisories/GHSA-6fc8-4gx4-v693"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2021-32640"
    },
    {
      "type": "WEB",
      "url": "https://github.com/websockets/ws/issues/1895"
    },
    {
      "type": "WEB",
      "url": "https://github.com/websockets/ws/commit/00c425ec77993773d823f018f64a5c44e17023ff"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/websockets/ws"
    },
    {
      "type": "WEB",
      "url": "https://lists.apache.org/thread.html/rdfa7b6253c4d6271e31566ecd5f30b7ce1b8fb2c89d52b8c4e0f4e30@%3Ccommits.tinkerpop.apache.org%3E"
    },
    {
      "type": "WEB",
      "url": "https://security.netapp.com/advisory/ntap-20210706-0005"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L",
      "type": "CVSS_V3"
    }
  ],
  "summary": "ReDoS in Sec-Websocket-Protocol header"
}


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