alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE MixShell CnC Activity (GET)"; flow:established,to_server; flowbits:set,ET.MixShell.herokuapp; http.method; content:"GET"; http.uri; bsize:107; pcre:"/^\x2f(?:[a-z0-9]{106})$/R"; http.host; content:".herokuapp.com"; endswith; fast_pattern; http.user_agent; content:"Chrome/120.0.0.0"; reference:url,research.checkpoint.com/2025/zipline-phishing-campaign; classtype:command-and-control; sid:2069095; rev:1; metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_Endpoint, tls_state TLSDecrypt, created_at 2026_04_30, deployment Perimeter, malware_family MixShell, confidence High, signature_severity Critical, tag c2, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2026_04_30, mitre_tactic_id TA0011, mitre_tactic_name Command_And_Control, mitre_technique_id T1071, mitre_technique_name Application_Layer_Protocol; target:src_ip;)