ET MALWARE Possible Drive DDoS Check-in

alert http $HOME_NET any -> $EXTERNAL_NET any (
    msg:"ET MALWARE Possible Drive DDoS Check-in";
    flow:established,to_server;
    flowbits:set,ET.Drive.DDoS.Checkin;
    http.method;
    content:"POST";
    http.header;
    pcre:"/-urlencoded\r\n(?:\r\n)?$/";
    http.request_body;
    content:"k="; fast_pattern; startswith;
    pcre:"/^[0-9]*?[a-z]/PR";
    http.content_len;
    byte_test:0,=,17,0,string,dec;
    http.header_names;
    content:!"Referer|0d 0a|";
    content:"|0d 0a|Host|0d 0a|"; startswith;
    classtype:trojan-activity;
    sid:2017045; rev:5;
    metadata:created_at 2013_06_22, confidence Medium, signature_severity Major, updated_at 2020_11_17;
)