alert tcp $EXTERNAL_NET any -> $HOME_NET any (msg:"ET MALWARE DeskRAT CnC HeartBeat Request"; flow:established,to_client; content:"|7b 22|type|22 3a 22|heartbeat|22 2c 22|timestamp|22 3a 22|"; depth:37; threshold:type limit,count 1,seconds 300,track by_src; classtype:command-and-control; sid:2066658; rev:1; metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_Endpoint, tls_state TLSDecrypt, created_at 2026_01_09, deployment Perimeter, deployment SSLDecrypt, malware_family DeskRAT, confidence High, signature_severity Critical, updated_at 2026_01_09, mitre_tactic_id TA0011, mitre_tactic_name Command_And_Control, mitre_technique_id T1041, mitre_technique_name Exfiltration_Over_C2_Channel; target:dest_ip;)