ET MALWARE Win32/Vermilion Stager Activity (GET)

alert http $HOME_NET any -> $EXTERNAL_NET any (
    msg:"ET MALWARE Win32/Vermilion Stager Activity (GET)";
    flow:established,to_server;
    http.method;
    content:"GET";
    http.uri;
    content:"/g.pixel"; bsize:8; fast_pattern;
    http.host;
    pcre:"/^\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}$/";
    http.header_names;
    content:!"Referer";
    content:"|0d 0a|Content-Type|0d 0a|Cookie|0d 0a|User-Agent|0d 0a|Host|0d 0a|Cache-Control|0d 0a 0d 0a|";
    http.cookie;
    pcre:"/(?:[A-Za-z0-9+/]{4})*(?:[A-Za-z0-9+/]{2}==|[A-Za-z0-9+/]{3}=|[A-Za-z0-9+/]{4})$/";
    reference:md5,6310a2c9f45fd46cd405e31eda2ad7d3;
    reference:url,www.intezer.com/blog/malware-analysis/vermilionstrike-reimplementation-cobaltstrike/;
    classtype:trojan-activity;
    sid:2033931; rev:1;
    metadata:created_at 2021_09_13, malware_family Win32_Vermilion, confidence High, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2021_09_13;
)