Web Socket URL poisoning (stored DOM-based)
Summary: PortSwigger describes stored DOM-based WebSocket URL poisoning, where user input is stored and later embedded into the DOM, and a client-side script uses that controllable data as the target URL of a WebSocket connection. An attacker can construct a URL that, when visited by another user, causes that user's browser to open a WebSocket connection to a URL under the attacker's control.
What's compelling: The impact depends on what the application sends over the socket: if sensitive data moves from the user's browser to the WebSocket server, the attacker may capture it, and if the application processes data read from the server, the attacker may subvert application logic or deliver further client-side attacks.
Read the original at PortSwigger Research ↗
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