alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE Cobalt Strike ScreenShot Exfil (POST)"; flow:established,to_server; urilen:9; http.method; content:"POST"; http.uri; content:"|2f|upload|5f|1"; fast_pattern; http.request_body; content:"Content|2d|Disposition|3a 20|form|2d|data|3b 20|name|3d 22|file|22 3b 20|filename|3d 22|"; pcre:"/^(?:[a-zA-Z0-9]{10,20})/R"; content:"|2e|jpeg|22|"; within:6; threshold:type limit,count 1,seconds 300,track by_src; classtype:trojan-activity; sid:2065231; 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;)