alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE ShadowAgent/TA396 CnC Activity (POST) M2"; flow:established,to_server; http.method; content:"POST"; http.uri; bsize:>20; pcre:"/^\x2f(?:[a-zA-Z0-9\x2f\x2d\x3d\x2b]){18}/"; http.content_type; content:"application/x-www-form-urlencoded"; http.header; content:"Cache-Control|3a 20|no-cache|0d 0a|"; http.request_body; content:"batac="; startswith; fast_pattern; pcre:"/^(?:[a-zA-Z0-9\x2f\x2d\x3d\x2b]){30}/R"; threshold:type limit,count 1,seconds 300,track by_src; reference:url,mp.weixin.qq.com/s?__biz=MzUyMjk4NzExMA==&mid=2247507603&idx=1&sn=af41be456f6393a24771846328e8d7f2&chksm=f9c1ed9aceb6648ce3bc17578a9255fc21c310815312dc066e133762b9b088b365eaa831b734&scene=178&cur_album_id=1955835290309230595&search_click_id; classtype:command-and-control; sid:2066181; rev:1; metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_Endpoint, tls_state TLSDecrypt, created_at 2025_12_08, deployment Perimeter, deployment SSLDecrypt, confidence High, signature_severity Critical, tag c2, tag TA396, updated_at 2025_12_08, mitre_tactic_id TA0011, mitre_tactic_name Command_And_Control, mitre_technique_id T1071, mitre_technique_name Application_Layer_Protocol; target:src_ip;)