# Online Chatroom


For this challenge, we get the source code of a Go binary. We notice some chat messages going on and the flag is within the chat history of user 5.


Sending a simple message in the web application:


And intercepting it with Burpsuite, we notice it is using websockets:


In the source code, we notice another command other than `!write`. We notice we can query the chat history using `!history`. After sending the request to Repeater, we see we need to provide an index from 1 to 7.


Well, what happens if we query outside of that range?


We get the flag: flag{c398112ed498fa2cacc41433a3e3190b}

Original writeup (https://github.com/LazyTitan33/CTF-Writeups/blob/main/Nahamcon2023/Warmups/Online_Chatroom.md).