Invoke-Obfuscation COMPRESS OBFUSCATION — Sigma Rule

Rule metadata and linked tags

Author: Timur Zinniatullin, oscd.community. Source status: test; severity: medium. Source dates: 2020-10-18 / 2022-12-29.

{
  "category": "process_creation",
  "product": "windows"
}

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: f4c6836a380403c183d58cd7f3f70ab239b99794f5d6ebfdb23dbdbab8e93253

Detection logic

Original source YAML. Source-tag agreement is not proof of complete semantic coverage. This rule has not been compiled for a SIEM backend or validated against live telemetry here.

title: Invoke-Obfuscation COMPRESS OBFUSCATION
id: 7eedcc9d-9fdb-4d94-9c54-474e8affc0c7
status: test
description: Detects Obfuscated Powershell via COMPRESS OBFUSCATION
references:
    - https://github.com/SigmaHQ/sigma/issues/1009 # (Task 19)
author: Timur Zinniatullin, oscd.community
date: 2020-10-18
modified: 2022-12-29
tags:
    - attack.stealth
    - attack.t1027
    - attack.execution
    - attack.t1059.001
logsource:
    category: process_creation
    product: windows
detection:
    selection:
        CommandLine|contains|all:
            - 'new-object'
            - 'text.encoding]::ascii'
        CommandLine|contains:
            - 'system.io.compression.deflatestream'
            - 'system.io.streamreader'
            - 'readtoend('
    condition: selection
falsepositives:
    - Unknown
level: medium

Original YAML and metadata in JSON

False positives

• Unknown

Source references

• https://github.com/SigmaHQ/sigma/issues/1009