alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET INFO WebSocket Session Initiation Request"; flow:established,to_server; flowbits:set,ETPRO.WebSocket.Request; http.connection; bsize:7; content:"Upgrade"; fast_pattern; nocase; http.header; header_lowercase; content:"upgrade|3a 20|websocket|0d 0a|"; reference:url,tools.ietf.org/html/rfc6455; classtype:not-suspicious; sid:2036219; rev:6; metadata:created_at 2014_09_17, deployment alert_only, confidence High, signature_severity Informational, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2024_05_05;)