ET MALWARE SoulSearcher Checkin M2

alert http $HOME_NET any -> $EXTERNAL_NET any (
    msg:"ET MALWARE SoulSearcher Checkin M2";
    flow:established,to_server;
    http.method;
    content:"GET";
    http.uri;
    content:"/en-my/CMSStyles/style.csx?k="; startswith; fast_pattern;
    http.host;
    content:"c.s-microsoft.com";
    http.request_body;
    content:"|00 00 00 11|"; startswith;
    byte_jump:4,8,relative,little,post_offset -1;
    isdataat:!2,relative;
    content:"|78 9c|"; offset:16; depth:2;
    reference:url,www.fortinet.com/blog/threat-research/unraveling-the-evolution-of-the-soul-searcher-malware;
    classtype:command-and-control;
    sid:2035416; rev:2;
    metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_Endpoint, created_at 2022_03_09, deployment Perimeter, performance_impact Low, confidence High, signature_severity Major, tag c2, updated_at 2022_03_09, mitre_tactic_id TA0011, mitre_tactic_name Command_And_Control, mitre_technique_id T1071, mitre_technique_name Application_Layer_Protocol;
)