alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE Cobalt Strike Beacon Activity"; flow:established,to_server; http.method; content:"GET"; http.uri; content:".gif?utmac="; fast_pattern; content:"&utmcn="; distance:0; content:"&utmcs="; distance:0; http.header_names; content:!"|0d 0a|Referer|0d 0a|"; content:!"|0d 0a|referer|0d 0a|"; reference:url,twitter.com/MichalKoczwara/status/1377651431478595588; reference:md5,db9214c2f8340ceba664800481f0ca08; classtype:trojan-activity; sid:2032362; rev:2; metadata:attack_target Client_Endpoint, created_at 2021_04_01, deployment Perimeter, deployment SSLDecrypt, confidence Medium, signature_severity Major, tag c2, updated_at 2023_09_12, reviewed_at 2024_03_12, mitre_tactic_id TA0010, mitre_tactic_name Exfiltration, mitre_technique_id T1041, mitre_technique_name Exfiltration_Over_C2_Channel;)