alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE W32/GCman.Backdoor CnC Beacon"; flow:established,to_server; http.method; content:"POST"; http.uri; content:"/cgi-bin/s2.cgi"; depth:15; http.request_body; pcre:"/^[a-f0-9]{31}\x3B(?:[a-zA-Z0-9+/=]+)?\r?$/"; http.header_names; content:!"Referer|0d 0a|"; reference:md5,8a18846e17244db9af90009ddab341ce; reference:url,securelist.com/blog/research/73638/apt-style-bank-robberies-increase-with-metel-gcman-and-carbanak-2-0-attacks/; classtype:command-and-control; sid:2022529; rev:3; metadata:attack_target Client_Endpoint, created_at 2016_02_17, deployment Perimeter, signature_severity Major, tag c2, updated_at 2020_06_24, mitre_tactic_id TA0010, mitre_tactic_name Exfiltration, mitre_technique_id T1041, mitre_technique_name Exfiltration_Over_C2_Channel;)