alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE W32/BlackEnergy Dirconf CnC Beacon"; flow:established,to_server; http.uri; content:"/dirconf/check.php"; fast_pattern; http.header; pcre:"/^Host\x3a\x20\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}(?:\x3a\d{1,5})?\r?$/mi"; reference:url,www.f-secure.com/weblog/archives/00002721.html; classtype:command-and-control; sid:2019412; rev:4; metadata:attack_target Client_Endpoint, created_at 2014_10_15, deployment Perimeter, signature_severity Major, tag c2, updated_at 2020_09_25, mitre_tactic_id TA0010, mitre_tactic_name Exfiltration, mitre_technique_id T1041, mitre_technique_name Exfiltration_Over_C2_Channel;)