ET MALWARE Sednit Connectivity Check 0 Byte POST

alert http $HOME_NET any -> $EXTERNAL_NET any (
    msg:"ET MALWARE Sednit Connectivity Check 0 Byte POST";
    flow:to_server,established;
    http.method;
    content:"POST";
    http.uri;
    content:!"=http";
    content:"/?";
    pcre:"/\.[a-z]{3,4}\/\?[A-Za-z0-9]+=(?:[A-Za-z0-9+/]{4})*(?:[A-Za-z0-9+/]{2}==|[A-Za-z0-9+/]{3}=|[A-Za-z0-9+/]{4})$/";
    http.header;
    content:"Content-Length|3a 20|0|0D 0A|"; fast_pattern;
    http.host;
    content:"google."; within:10;
    pcre:"/^(?:www\.)?google(?:\.[a-z]{2,3})+$/";
    http.header_names;
    content:!"Referer|0d 0a|";
    reference:url,blog.trendmicro.com/trendlabs-security-intelligence/an-in-depth-look-at-how-pawn-storms-java-zero-day-was-used;
    classtype:targeted-activity;
    sid:2021506; rev:7;
    metadata:created_at 2015_07_22, performance_impact Significant, signature_severity Major, updated_at 2024_04_29;
)