alert tcp $HOME_NET any <> $EXTERNAL_NET [1000,1001,1002] (msg:"ET MALWARE upStage Proxy Heartbeat"; flow:established,to_server; dsize:2; content:"|05 00|"; fast_pattern; threshold:type limit,track by_src,count 5,seconds 120; reference:url,github.com/ShadowOpCode/DesckVB-RAT/tree/main; reference:md5,8f2f2b1a5666036ef7be2cd4d42eb281; classtype:trojan-activity; sid:2067604; rev:1; metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_Endpoint, tls_state plaintext, created_at 2026_02_11, deployment Perimeter, performance_impact Significant, confidence High, signature_severity Major, tag RAT, updated_at 2026_02_11, mitre_tactic_id TA0011, mitre_tactic_name Command_And_Control, mitre_technique_id T1090, mitre_technique_name Proxy;)