Version Details and Security Vulnerabilities

Affected versions of socket.io depend on Math.random() to create socket IDs, and therefore the IDs are predictable. With enough information on prior IDs, an attacker may be able to guess the socket ID and gain access to socket.io servers without authorization.

Recommendation

Update to v0.9.7 or later.

The package socket.io before 2.4.0 are vulnerable to Insecure Defaults due to CORS Misconfiguration. All domains are whitelisted by default.

Impact

A specially crafted Socket.IO packet can trigger an uncaught exception on the Socket.IO server, thus killing the Node.js process.

node:events:502
    throw err; // Unhandled 'error' event
    ^

Error [ERR_UNHANDLED_ERROR]: Unhandled error. (undefined)
    at new NodeError (node:internal/errors:405:5)
    at Socket.emit (node:events:500:17)
    at /myapp/node_modules/socket.io/lib/socket.js:531:14
    at process.processTicksAndRejections (node:internal/process/task_queues:77:11) {
  code: 'ERR_UNHANDLED_ERROR',
  context: undefined
}

Affected versions

| Version range | Needs minor update? | |------------------|------------------------------------------------| | 4.6.2...latest | Nothing to do | | 3.0.0...4.6.1 | Please upgrade to socket.io@4.6.2 (at least) | | 2.3.0...2.5.0 | Please upgrade to socket.io@2.5.1 |

Patches

This issue is fixed by https://github.com/socketio/socket.io/commit/15af22fc22bc6030fcead322c106f07640336115, included in socket.io@4.6.2 (released in May 2023).

The fix was backported in the 2.x branch today: https://github.com/socketio/socket.io/commit/d30630ba10562bf987f4d2b42440fc41a828119c

Workarounds

As a workaround for the affected versions of the socket.io package, you can attach a listener for the "error" event:

io.on("connection", (socket) => {
  socket.on("error", () => {
    // ...
  });
});

For more information

If you have any questions or comments about this advisory:

• Open a discussion here

Thanks a lot to Paul Taylor for the responsible disclosure.

References

• https://github.com/socketio/socket.io/commit/15af22fc22bc6030fcead322c106f07640336115
• https://github.com/socketio/socket.io/commit/d30630ba10562bf987f4d2b42440fc41a828119c

Versions of uglify-js prior to 2.4.24 are affected by a vulnerability which may cause crafted JavaScript to have altered functionality after minification.

Recommendation

Upgrade UglifyJS to version >= 2.4.24.

Versions of uglify-js prior to 2.6.0 are affected by a regular expression denial of service vulnerability when malicious inputs are passed into the parse() method.

Proof of Concept

var u = require('uglify-js');
var genstr = function (len, chr) {
    var result = "";
    for (i=0; i<=len; i++) {
        result = result + chr;
    }

    return result;
}

u.parse("var a = " + genstr(process.argv[2], "1") + ".1ee7;");

Results

$ time node test.js 10000
real	0m1.091s
user	0m1.047s
sys	0m0.039s

$ time node test.js 80000
real	0m6.486s
user	0m6.229s
sys	0m0.094s

Recommendation

Update to version 2.6.0 or later.

This affects the package xmlhttprequest before 1.7.0; all versions of package xmlhttprequest-ssl. Provided requests are sent synchronously (async=False on xhr.open), malicious user input flowing into xhr.send could result in arbitrary code being injected and run.