Cross-site Scripting (XSS) - Stored in convos-chat/convos
Dec 29th 2021
The Convos is an open source multi-user chat that runs in a web browser. Characters starting with "https://" in the chat window create <a> tag. Stored XSS vulnerability using onfocus and autofocus occurs because escaping exists for "<" or ">" but escaping for double quarter does not exist.
Proof of Concept
Username : firstname.lastname@example.org Password : qwer12211@ 1. Open the https://demo.convos.chat/login and Login as to above account 2. Go to https://demo.convos.chat/chat/irc-demo-irc-convos/<chat room name> 3. In chat room. Enter the https://x."//onfocus="alert(document.domain)"//autofocus="" b=" Video : https://www.youtube.com/watch?v=L1Be-D-GVmQ
Through this vulnerability, an attacker is capable to execute malicious scripts.