GHSA-qm95-pgcg-qqfq

Suggest an improvement
Source
https://github.com/advisories/GHSA-qm95-pgcg-qqfq
Import Source
https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2022/10/GHSA-qm95-pgcg-qqfq/GHSA-qm95-pgcg-qqfq.json
JSON Data
https://api.osv.dev/v1/vulns/GHSA-qm95-pgcg-qqfq
Aliases
Published
2022-10-26T12:00:28Z
Modified
2023-11-08T04:08:29.946069Z
Severity
  • 9.8 (Critical) CVSS_V3 - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H CVSS Calculator
Summary
Insufficient validation when decoding a Socket.IO packet
Details

Due to improper type validation in the socket.io-parser library (which is used by the socket.io and socket.io-client packages to encode and decode Socket.IO packets), it is possible to overwrite the _placeholder object which allows an attacker to place references to functions at arbitrary places in the resulting query object.

Example:

const decoder = new Decoder();

decoder.on("decoded", (packet) => {
 console.log(packet.data); // prints [ 'hello', [Function: splice] ]
})

decoder.add('51-["hello",{"_placeholder":true,"num":"splice"}]');
decoder.add(Buffer.from("world"));

This bubbles up in the socket.io package:

io.on("connection", (socket) => {
 socket.on("hello", (val) => {
 // here, "val" could be a function instead of a buffer
 });
});

:warning: IMPORTANT NOTE :warning:

You need to make sure that the payload that you received from the client is actually a Buffer object:

io.on("connection", (socket) => {
 socket.on("hello", (val) => {
 if (!Buffer.isBuffer(val)) {
 socket.disconnect();
 return;
 }
 // ...
 });
});

If that's already the case, then you are not impacted by this issue, and there is no way an attacker could make your server crash (or escalate privileges, ...).

Example of values that could be sent by a malicious user:

  • a number that is out of bounds

Sample packet: 451-["hello",{"_placeholder":true,"num":10}]

io.on("connection", (socket) => {
 socket.on("hello", (val) => {
 // val is `undefined`
 });
});
  • a value that is not a number, like undefined

Sample packet: 451-["hello",{"_placeholder":true,"num":undefined}]

io.on("connection", (socket) => {
 socket.on("hello", (val) => {
 // val is `undefined`
 });
});
  • a string that is part of the prototype of Array, like "push"

Sample packet: 451-["hello",{"_placeholder":true,"num":"push"}]

io.on("connection", (socket) => {
 socket.on("hello", (val) => {
 // val is a reference to the "push" function
 });
});
  • a string that is part of the prototype of Object, like "hasOwnProperty"

Sample packet: 451-["hello",{"_placeholder":true,"num":"hasOwnProperty"}]

io.on("connection", (socket) => {
 socket.on("hello", (val) => {
 // val is a reference to the "hasOwnProperty" function
 });
});

This should be fixed by:

  • https://github.com/socketio/socket.io-parser/commit/b5d0cb7dc56a0601a09b056beaeeb0e43b160050, included in socket.io-parser@4.2.1
  • https://github.com/socketio/socket.io-parser/commit/b559f050ee02bd90bd853b9823f8de7fa94a80d4, included in socket.io-parser@4.0.5
  • https://github.com/socketio/socket.io-parser/commit/04d23cecafe1b859fb03e0cbf6ba3b74dff56d14, included in socket.io-parser@3.4.2
  • https://github.com/socketio/socket.io-parser/commit/fb21e422fc193b34347395a33e0f625bebc09983, included in socket.io-parser@3.3.3

Dependency analysis for the socket.io package

| socket.io version | socket.io-parser version | Covered? | |---------------------|---------------------------------------------------------------------------------------------------------|------------------------| | 4.5.2...latest | ~4.2.0 (ref) | Yes :heavycheckmark: | | 4.1.3...4.5.1 | ~4.0.4 (ref) | Yes :heavycheckmark: | | 3.0.5...4.1.2 | ~4.0.3 (ref) | Yes :heavycheckmark: | | 3.0.0...3.0.4 | ~4.0.1 (ref) | Yes :heavycheckmark: | | 2.3.0...2.5.0 | ~3.4.0 (ref) | Yes :heavycheckmark: |

Dependency analysis for the socket.io-client package

| socket.io-client version | socket.io-parser version | Covered? | |----------------------------|----------------------------------------------------------------------------------------------------------------|------------------------------------| | 4.5.0...latest | ~4.2.0 (ref) | Yes :heavycheckmark: | | 4.3.0...4.4.1 | ~4.1.1 (ref) | No, but the impact is very limited | | 3.1.0...4.2.0 | ~4.0.4 (ref) | Yes :heavycheckmark: | | 3.0.5 | ~4.0.3 (ref) | Yes :heavycheckmark: | | 3.0.0...3.0.4 | ~4.0.1 (ref) | Yes :heavycheckmark: | | 2.2.0...2.5.0 | ~3.3.0 (ref) | Yes :heavycheckmark: |

References

Affected packages

npm / socket.io-parser

Package

Affected ranges

Type
SEMVER
Events
Introduced
4.0.0
Fixed
4.0.5

Ecosystem specific

{
    "affected_functions": [
        "(socket.io-parser).Decoder"
    ]
}

npm / socket.io-parser

Package

Affected ranges

Type
SEMVER
Events
Introduced
4.1.0
Fixed
4.2.1

Ecosystem specific

{
    "affected_functions": [
        "(socket.io-parser).Decoder"
    ]
}

npm / socket.io-parser

Package

Affected ranges

Type
SEMVER
Events
Introduced
0Unknown introduced version / All previous versions are affected
Fixed
3.3.3

Ecosystem specific

{
    "affected_functions": [
        "(socket.io-parser).Decoder"
    ]
}

npm / socket.io-parser

Package

Affected ranges

Type
SEMVER
Events
Introduced
3.4.0
Fixed
3.4.2

Ecosystem specific

{
    "affected_functions": [
        "(socket.io-parser).Decoder"
    ]
}