alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE W32/Adrom.Backdoor CnC Beacon"; flow:established,to_server; http.method; content:"GET"; http.uri; content:".php?page="; content:"&enckey="; fast_pattern; pcre:"/\x26enckey\x3D[A-F0-9]+$/"; http.header_names; content:!"Referer|0d 0a|"; reference:md5,c621055803c68e89f3cb141608fd0894; reference:md5,3c2be5202d2d68047c76bdf7e1dfc2be; classtype:command-and-control; sid:2020293; rev:4; metadata:attack_target Client_Endpoint, created_at 2015_01_23, deployment Perimeter, signature_severity Major, tag c2, updated_at 2020_09_29, mitre_tactic_id TA0010, mitre_tactic_name Exfiltration, mitre_technique_id T1041, mitre_technique_name Exfiltration_Over_C2_Channel;)