ET MALWARE Possible PowerShell Empire Activity Outbound

alert http $HOME_NET any -> $EXTERNAL_NET any (
    msg:"ET MALWARE Possible PowerShell Empire Activity Outbound";
    flow:established,to_server;
    http.method;
    content:"GET";
    http.uri;
    content:"/"; depth:1;
    pcre:"/^(?:login\/process|admin\/get|news)\.php$/R";
    http.user_agent;
    content:"Mozilla|2f|5.0|20 28|Windows|20|NT|20|6.1";
    http.cookie;
    content:"session=";
    pcre:"/^(?:[A-Z0-9+/]{4})*(?:[A-Z0-9+/]{2}==|[A-Z0-9+/]{3}=|[A-Z0-9+/]{4})$/Ri";
    http.start;
    content:".php|20|HTTP|2f|1.1|0d 0a|Cookie|3a 20|session="; fast_pattern;
    http.header_names;
    content:!"Referer";
    content:!"Cache";
    content:!"Accept";
    classtype:trojan-activity;
    sid:2027512; rev:2;
    metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, created_at 2019_06_24, deployment Perimeter, performance_impact Low, confidence Medium, signature_severity Major, tag PowerShell_Empire, tag T1086, updated_at 2020_08_31;
)