alert tcp $EXTERNAL_NET any -> $HOME_NET any (msg:"ET MALWARE XiebroC2 CnC Activity KeepAlive M4 (Inbound)"; flow:established,to_server; dsize:<100; content:"|d0 ed a2 d7 3b 87 f3 cd fa 15 7c 93 c3 61 82 e4|"; startswith; reference:md5,f6eebd3486a9cabfd0542ce14e3a2718; 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:2058333; 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_16, deployment Perimeter, confidence High, signature_severity Major, tag c2, tag Xiebro, updated_at 2024_12_16, mitre_tactic_id TA0011, mitre_tactic_name Command_And_Control, mitre_technique_id T1071, mitre_technique_name Application_Layer_Protocol; target:src_ip;)