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

SID: 2026992

Revision: 5

Class Type: bad-unknown

Metadata: affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, created_at 2019_02_28, deployment alert_only, performance_impact Low, signature_severity Major, tag PowerShell, updated_at 2023_04_20, reviewed_at 2023_10_11

Reference:

Protocol: tcp

Source Network: $EXTERNAL_NET

Source Port: $HTTP_PORTS

Destination Network: $HOME_NET

Destination Port: any

Flow: established,to_client

Contents:

• Value: !"|22|manifestVersion|22|"

• Value: !"<html"

• Value: "powershell"

• Value: "|20|-e"

Within:

PCRE: "/^(?:nc)?\s(?:[A-Z0-9+\/]{4})(?:[A-Z0-9+\/]{2}==|[A-Z0-9+\/]{3}=)/Ri"

Special Options:

• file_data

• fast_pattern

• nocase

• nocase

source