ET MALWARE Windows Scriptlet Invoking Powershell Likely Malicious

alert http $EXTERNAL_NET any -> $HOME_NET any (
    msg:"ET MALWARE Windows Scriptlet Invoking Powershell Likely Malicious";
    flow:established,from_server;
    file_data;
    content:"WScript.shell"; nocase; fast_pattern;
    content:"ActiveXObject"; nocase;
    content:"<registration"; nocase; distance:0;
    content:"progid"; distance:0; nocase;
    content:"<script"; nocase; distance:0;
    content:"<![CDATA["; nocase; distance:0;
    pcre:"/^.{1,1000}p(?:[\x22\x27]\s*[\x26\x2b]\s*[\x22\x27])?(?:\^(?:[\x22\x27]\s*[\x26\x2b]\s*[\x22\x27])?)?o(?:[\x22\x27]\s*[\x26\x2b]\s*[\x22\x27])?(?:\^(?:[\x22\x27]\s*[\x26\x2b]\s*[\x22\x27])?)?w(?:[\x22\x27]\s*[\x26\x2b]\s*[\x22\x27])?(?:\^(?:[\x22\x27]\s*[\x26\x2b]\s*[\x22\x27])?)?e(?:[\x22\x27]\s*[\x26\x2b]\s*[\x22\x27])?(?:\^(?:[\x22\x27]\s*[\x26\x2b]\s*[\x22\x27])?)?r(?:[\x22\x27]\s*[\x26\x2b]\s*[\x22\x27])?(?:\^(?:[\x22\x27]\s*[\x26\x2b]\s*[\x22\x27])?)?s(?:[\x22\x27]\s*[\x26\x2b]\s*[\x22\x27])?(?:\^(?:[\x22\x27]\s*[\x26\x2b]\s*[\x22\x27])?)?h(?:[\x22\x27]\s*[\x26\x2b]\s*[\x22\x27])?(?:\^(?:[\x22\x27]\s*[\x26\x2b]\s*[\x22\x27])?)?e(?:[\x22\x27]\s*[\x26\x2b]\s*[\x22\x27])?(?:\^(?:[\x22\x27]\s*[\x26\x2b]\s*[\x22\x27])?)?l(?:[\x22\x27]\s*[\x26\x2b]\s*[\x22\x27])?(?:\^(?:[\x22\x27]\s*[\x26\x2b]\s*[\x22\x27])?)?l/Rsi";
    reference:url,www.carbonblack.com/2016/04/28/threat-advisory-squiblydoo-continues-trend-of-attackers-using-native-os-tools-to-live-off-the-land/;
    classtype:trojan-activity;
    sid:2024549; rev:4;
    metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_Endpoint, created_at 2017_08_15, deployment Perimeter, malware_family PowerShell, performance_impact Low, confidence Medium, signature_severity Major, tag PowerShell, updated_at 2020_08_19;
)