ET MALWARE Kimsuky CnC Chunked Exfil (POST)

alert http $HOME_NET any -> $EXTERNAL_NET any (
    msg:"ET MALWARE Kimsuky CnC Chunked Exfil (POST)";
    flow:established,to_server;
    http.method;
    content:"POST";
    http.uri;
    content:"/service"; startswith;
    content:"|2f 3f|id|3d|"; within:7;
    http.request_body;
    content:"name=file";
    content:"|20|filename|3d|init|2e|dat|3b 20|filename|2a 3d|utf|2d|8"; distance:0; fast_pattern;
    content:"init.dat|0d 0a|"; distance:0;
    reference:url,aryaka.com/blog/kimsuky-apt-stealth-malware-social-engineering;
    classtype:command-and-control;
    sid:2063830; rev:1;
    metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_Endpoint, tls_state plaintext, created_at 2025_06_24, deployment Perimeter, malware_family Kimsuky, confidence High, signature_severity Critical, tag c2, updated_at 2025_07_31, former_sid 2863012, mitre_tactic_id TA0011, mitre_tactic_name Command_And_Control, mitre_technique_id T1071, mitre_technique_name Application_Layer_Protocol;
    target:src_ip;
)