Rule History

alert http $EXTERNAL_NET any -> $HOME_NET any (msg:"ET MALWARE MixShell CnC Activity Response"; flow:established,to_client; flowbits:isset,ET.MixShell.herokuapp; content:"Server|3a 20|Heroku"; fast_pattern; http.response_body; pcre:"/^(?:[a-z0-9]{15,200})\x01\x00$/"; reference:url,research.checkpoint.com/2025/zipline-phishing-campaign; classtype:command-and-control; sid:2069096; 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, deployment SSLDecrypt, 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:dest_ip;)