alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE APT.Fwits CnC Beacon M2"; flow:established,to_server; http.method; content:"GET"; http.uri; content:"?---"; pcre:"/\?---[A-Z]$/"; http.header_names; to_lowercase; content:!"|0d 0a|user-agent|0d 0a|"; content:!"|0d 0a|accept"; content:!"|0d 0a|referer|0d 0a|"; reference:md5,24d76abbc0a10e4c977a28b33c879248; reference:url,baesystemsai.blogspot.com/2016/04/two-bytes-to-951m.html; classtype:targeted-activity; sid:2022757; rev:4; metadata:attack_target Client_Endpoint, created_at 2016_04_25, deployment Perimeter, signature_severity Major, tag c2, updated_at 2024_04_20, mitre_tactic_id TA0010, mitre_tactic_name Exfiltration, mitre_technique_id T1041, mitre_technique_name Exfiltration_Over_C2_Channel;)