It has been a while that I did not spot WebSockets used by malware. Yesterday I discovered an interesting piece of Powershell. Very small and almost undetected according to its Virustotal score (2/54). A quick reminder for those that don’t know what a “WebSocket” is. When you perform a classic HTTP request to a server, it replies with some data and closes the connection. WebSockets make the client/server push messages at any time without any relation to a previous request. Compared to HTTP, they allow bi-directional protocols, full-duplex and, over a single TCP connection.