ET ATTACK_RESPONSE PowerShell Base64 Encoded Content Command Common In Powershell Stagers M1

alert http $EXTERNAL_NET any -> $HOME_NET any (
    msg:"ET ATTACK_RESPONSE PowerShell Base64 Encoded Content Command Common In Powershell Stagers M1";
    flow:established,to_client;
    file.data;
    content:!"|22|manifestVersion|22|";
    content:!"<html";
    content:"powershell"; fast_pattern; nocase;
    content:"|20|-e"; nocase; distance:0;
    pcre:"/^(?:nc)?\s*(?:[A-Z0-9+\/]{4})*(?:[A-Z0-9+\/]{2}==|[A-Z0-9+\/]{3}=)/Ri";
    classtype:bad-unknown;
    sid:2026992; rev:5;
    metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, created_at 2019_02_28, deployment alert_only, performance_impact Low, confidence High, signature_severity Minor, tag PowerShell, updated_at 2024_12_12, reviewed_at 2023_10_11;
)