""ET TROJAN Possible Malicious Gzip PowerShell over HTTP""

SID: 2024221

Revision: 1

Class Type: trojan-activity

Metadata: affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_Endpoint, created_at 2017_04_18, deployment Perimeter, malware_family PowerShell, performance_impact Moderate, signature_severity Major, tag PowerShell, updated_at 2017_04_18

Reference:

Protocol: tcp

Source Network: $EXTERNAL_NET

Source Port: $HTTP_PORTS

Destination Network: $HOME_NET

Destination Port: any

Flow: established,from_server

Contents:

• Value: "FromBase64String"

• Value: "H4sIAI"

• Value: "GzipStream"

Within:

PCRE:

Special Options:

• file_data

• fast_pattern

• nocase

source