alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE IceCube JS Backdoor C2 Collect Info"; flow:established,to_server; http.uri; bsize:12; content:"/api/collect"; http.header_names; to_lowercase; content:"x-c2-token|0d 0a|"; fast_pattern; http.method; content:"POST"; reference:url,www.proofpoint.com/us/blog/threat-insight/one-email-closer-edge-unkmasstraction-physics-exploitation; classtype:trojan-activity; sid:2071123; rev:1; metadata:attack_target Client_Endpoint, created_at 2026_07_07, deployment Perimeter, deployment Internal, confidence High, signature_severity Major, tag c2, updated_at 2026_07_07, mitre_tactic_id TA0011, mitre_tactic_name Command_And_Control, mitre_technique_id T1071, mitre_technique_name Application_Layer_Protocol; target:src_ip;)