alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE Cobalt Strike Beacon Activity (UNC2447)"; flow:established,to_server; http.method; content:"GET"; http.uri; content:".htm"; endswith; http.user_agent; content:"|20 28|compatible|3b 20|"; content:"|3b 20|.NET4.0E|20 29|"; endswith; fast_pattern; reference:url,www.fireeye.com/blog/threat-research/2021/04/unc2447-sombrat-and-fivehands-ransomware-sophisticated-financial-threat.html; classtype:trojan-activity; sid:2032944; rev:1; metadata:attack_target Client_Endpoint, created_at 2021_05_11, deployment Perimeter, deployment SSLDecrypt, confidence Medium, signature_severity Major, tag c2, updated_at 2021_05_11, mitre_tactic_id TA0010, mitre_tactic_name Exfiltration, mitre_technique_id T1041, mitre_technique_name Exfiltration_Over_C2_Channel;)