ET MALWARE Ixeshe/Mecklow Checkin

alert http $HOME_NET any -> $EXTERNAL_NET any (
    msg:"ET MALWARE Ixeshe/Mecklow Checkin";
    flow:established,to_server;
    http.method;
    content:"GET";
    http.uri;
    content:!"&";
    content:".";
    content:"sp?"; distance:1; within:3;
    pcre:"/\/[A-Z0-9]+\.[aj]sp\?[a-zA-Z0-9+/\x20=]+$/";
    http.user_agent;
    content:"MSIE 5.01|3b 20|Windows NT 5.0|29|"; fast_pattern;
    http.header_names;
    content:!"Accept";
    content:!"Referer";
    reference:url,www.microsoft.com/security/portal/Threat/Encyclopedia/Entry.aspx?Name=Backdoor%3aWin32%2fMecklow.A&ThreatID=-2147325849;
    reference:md5,3422e76cf4c99ec1091f8c342a3aedaa;
    reference:url,www.kahusecurity.com/2011/apec-spearphish-2/;
    classtype:command-and-control;
    sid:2018379; rev:12;
    metadata:created_at 2011_04_26, signature_severity Major, updated_at 2020_08_17;
)