ET RETIRED Win32/Koi Loader CnC Checkin M2

alert http $HOME_NET any -> $EXTERNAL_NET any (
    msg:"ET RETIRED Win32/Koi Loader CnC Checkin M2";
    flow:established,to_server;
    http.method;
    content:"POST";
    http.uri;
    content:"/config.php";
    http.content_type;
    content:"application/octet-stream";
    http.header;
    content:"Content-Encoding|3a 20|binary|0d 0a|";
    http.content_len;
    byte_test:0,=,86,0,string,dec;
    http.request_body;
    content:"111|7c|"; startswith; fast_pattern;
    pcre:"/^[a-f0-9]{8}-([a-f0-9]{4}-){3}[a-f0-9]{12}\x7c/R";
    reference:md5,09350493580399e2983148e80fd4490b;
    classtype:trojan-activity;
    sid:2049814; rev:2;
    metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, affected_product Windows_11, attack_target Client_Endpoint, created_at 2023_12_21, deployment Perimeter, former_category MALWARE, malware_family Win32_Koi, performance_impact Low, confidence High, signature_severity Major, updated_at 2025_04_17, reviewed_at 2025_04_17;
    target:src_ip;
)