alert tcp-pkt $HOME_NET any -> $EXTERNAL_NET 1024: (msg:"ET MALWARE MSIL/Crimson Client Command Response (info)"; flow:established,to_server; content:"|00 00 00 00|"; offset:1; depth:4; content:"inx7fo=usder"; distance:0; fast_pattern; content:"|00 00 00 00 7c|"; distance:1; within:5; content:"|7c|"; distance:0; content:"|7c|"; distance:0; content:"|7c|"; distance:0; threshold:type limit, track by_src, count 5, seconds 600; reference:md5,fdd625f11ae39b85d4c0f794e8570abe; classtype:command-and-control; sid:2036244; rev:3; metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_Endpoint, created_at 2022_04_18, deployment Perimeter, malware_family Crimson, confidence High, signature_severity Major, tag c2, updated_at 2023_03_14, mitre_tactic_id TA0010, mitre_tactic_name Exfiltration, mitre_technique_id T1041, mitre_technique_name Exfiltration_Over_C2_Channel;)