alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE IcedID WebSocket Request"; flow:established,to_server; http.method; content:"GET"; http.uri; content:"/data2.php?"; pcre:"/^[A-F0-9]{16}$/R"; http.header; content:"Upgrade|3a 20|websocket|0d 0a|Connection|3a 20|Upgrade|0d 0a|"; endswith; http.header_names; content:!"Referer"; content:!"Accept"; reference:md5,b17a729efb71d1781405c6c00052c85e; classtype:trojan-activity; sid:2026673; rev:5; metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_Endpoint, created_at 2018_11_29, deployment Perimeter, malware_family IcedID, confidence High, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2020_09_16;)