alert tcp $EXTERNAL_NET any -> $HOME_NET any (msg:"ET MALWARE XiebroC2 CnC Activity KeepAlive M2 (Inbound)"; flow:established,to_server; dsize:<100; content:"|a9 f3 62 f1 bb 31 bc cd dc f7 b9 80 d0 cd 95 cf|"; startswith; reference:md5,431e275f4e43ec4ef7c2cc8ba126e9d3; reference:url,news.sophos.com/en-us/2024/09/10/crimson-palace-new-tools-tactics-targets/; reference:url,github.com/INotGreen/XiebroC2/; classtype:command-and-control; sid:2058242; rev:1; metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, affected_product Linux, attack_target Client_Endpoint, created_at 2024_12_12, deployment Perimeter, confidence High, signature_severity Major, tag c2, tag Xiebro, updated_at 2024_12_12, mitre_tactic_id TA0011, mitre_tactic_name Command_And_Control, mitre_technique_id T1071, mitre_technique_name Application_Layer_Protocol; target:dest_ip;)