alert tcp $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE Win32/Remcos RAT Checkin 756"; flow:established,to_server; content:"|bf cd 35 03 80 a5 a0 21 05 b6 42|"; startswith; fast_pattern; content:"|8c 21|"; distance:2; within:2; threshold:type limit, seconds 30, count 1, track by_src; classtype:command-and-control; sid:2034236; rev:1; metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_Endpoint, created_at 2021_10_05, deployment Perimeter, malware_family Remcos, performance_impact Low, confidence High, signature_severity Major, tag RAT, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2021_10_05, mitre_tactic_id TA0010, mitre_tactic_name Exfiltration, mitre_technique_id T1041, mitre_technique_name Exfiltration_Over_C2_Channel;)