alert http $HOME_NET any -> $EXTERNAL_NET any (
msg:"ET MALWARE Cobalt Strike CnC Checkin (Submit Result)";
flow:established,to_server;
urilen:14;
http.method;
content:"POST";
http.uri;
content:"|2f|submit|5f|result"; fast_pattern;
http.request_body;
content:"token|3d|"; startswith;
pcre:"/^(?:[a-zA-Z0-9]{39})/R";
content:"|26|mac|3d|";
content:"|26|result|3d|"; distance:0;
threshold:type limit,count 1,seconds 300,track by_src;
classtype:trojan-activity;
sid:2065230; rev:1;
metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_Endpoint, tls_state plaintext, created_at 2025_10_16, deployment Perimeter, malware_family CobaltStrike, confidence High, signature_severity Critical, tag c2, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2025_10_16, mitre_tactic_id TA0011, mitre_tactic_name Command_And_Control, mitre_technique_id T1071, mitre_technique_name Application_Layer_Protocol;
target:src_ip;
)