ET MALWARE W32/Asprox.Bot Knock Variant CnC Beacon

alert http $HOME_NET any -> $EXTERNAL_NET any (
    msg:"ET MALWARE W32/Asprox.Bot Knock Variant CnC Beacon";
    flow:established,to_server;
    http.method;
    content:"POST";
    http.uri;
    pcre:"/^\x2F[A-F0-9]{20,}+$/";
    http.header_names;
    content:!"Referer";
    http.host;
    pcre:"/^\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}(?:\x3a\d{1,5})$/i";
    http.request_body;
    content:"<knock>"; fast_pattern; depth:7;
    content:"<ID>"; within:6;
    content:"<group>"; distance:0;
    content:"<version>"; distance:0;
    content:"<status>"; distance:0;
    reference:url,www.fireeye.com/blog/technical/malware-research/2014/06/a-not-so-civic-duty-asprox-botnet-campaign-spreads-court-dates-and-malware.html;
    classtype:command-and-control;
    sid:2018574; rev:3;
    metadata:attack_target Client_Endpoint, created_at 2014_06_17, deployment Perimeter, signature_severity Major, tag c2, updated_at 2020_04_30, mitre_tactic_id TA0010, mitre_tactic_name Exfiltration, mitre_technique_id T1041, mitre_technique_name Exfiltration_Over_C2_Channel;
)