alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE FIN12 Related WHITEDAGGER/Cobalt Strike Beacon Activity (GET)"; flow:established,to_server; http.request_line; content:"GET|20|/files/remove.gif|20|HTTP/1.1"; fast_pattern; http.header_names; content:"|0d 0a|Host|0d 0a|Accept|0d 0a|User-Agent|0d 0a|Connection|0d 0a|Cache-Control|0d 0a 0d 0a|"; bsize:57; reference:md5,cf3027fa4e3d5597487691dff1831b97; reference:url,www.mandiant.com/resources/fin12-ransomware-intrusion-actor-pursuing-healthcare-targets; classtype:trojan-activity; sid:2034185; rev:1; metadata:attack_target Client_Endpoint, created_at 2021_10_13, deployment Perimeter, deployment SSLDecrypt, malware_family CobaltStrike, malware_family Fin12, confidence Medium, signature_severity Major, tag c2, updated_at 2021_10_13, mitre_tactic_id TA0010, mitre_tactic_name Exfiltration, mitre_technique_id T1041, mitre_technique_name Exfiltration_Over_C2_Channel;)