alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE Felismus CnC Beacon 2"; flow:established,to_server; threshold:type limit, track by_src, count 1, seconds 600; http.method; content:"POST"; http.uri; content:"/products.php?"; fast_pattern; pcre:"/\.php\?[a-z]{15,}$/"; http.header; content:"Referer|3a|"; content:"/products.php|0d 0a|"; distance:0; http.request_body; pcre:"/^(?:[A-Za-z0-9+/]{4})*(?:[A-Za-z0-9+/]{2}==|[A-Za-z0-9+/]{3}=|[A-Za-z0-9+/]{4})$/"; http.header_names; content:!"Content-Type|0d 0a|"; reference:url,blogs.forcepoint.com/security-labs/playing-cat-mouse-introducing-felismus-malware; reference:md5,8de3f20d94611e0200c484e42093f447; classtype:command-and-control; sid:2024177; rev:5; metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_Endpoint, created_at 2017_04_04, deployment Perimeter, malware_family Felismus, confidence High, signature_severity Major, tag Felismus, tag c2, updated_at 2020_10_13, mitre_tactic_id TA0010, mitre_tactic_name Exfiltration, mitre_technique_id T1041, mitre_technique_name Exfiltration_Over_C2_Channel;)