ET MALWARE APT32 Win32/Ratsnif CnC Checkin

alert http $HOME_NET any -> $EXTERNAL_NET any (
    msg:"ET MALWARE APT32 Win32/Ratsnif CnC Checkin";
    flow:established,to_server;
    http.method;
    content:"POST";
    http.uri;
    content:"/cl_client_online.php"; depth:21; endswith;
    http.request_body;
    content:"Q29tcHV0ZXJOYW1lPV"; depth:18; fast_pattern;
    pcre:"/^(?:[A-Z0-9+/]{4})*(?:[A-Z0-9+/]{2}==|[A-Z0-9+/]{3}=|[A-Z0-9+/]{4})$/i";
    reference:url,threatvector.cylance.com/en_us/home/threat-spotlight-ratsnif-new-network-vermin-from-oceanlotus.html;
    reference:md5,516ad28f8fa161f086be7ca122351edf;
    classtype:targeted-activity;
    sid:2027659; rev:3;
    metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, created_at 2019_07_02, deployment Perimeter, malware_family Ratsnif, performance_impact Low, confidence High, signature_severity Major, tag APT32, updated_at 2020_09_17;
)