Suspicious Mount-DiskImage — Sigma Rule

Rule metadata and linked tags

Author: frack113. Source status: test; severity: low. Source dates: 2022-02-01 / not supplied.

{
  "product": "windows",
  "category": "ps_script",
  "definition": "Requirements: Script Block Logging must be enabled"
}

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: a5a76b2e30b34519efe68a65f5683f16a6521bcec8628b080b070b35557aa14f

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: Suspicious Mount-DiskImage
id: 29e1c216-6408-489d-8a06-ee9d151ef819
status: test
description: Adversaries may abuse container files such as disk image (.iso, .vhd) file formats to deliver malicious payloads that may not be tagged with MOTW.
references:
    - https://github.com/redcanaryco/atomic-red-team/blob/f339e7da7d05f6057fdfcdd3742bfcf365fee2a9/atomics/T1553.005/T1553.005.md#atomic-test-1---mount-iso-image
    - https://learn.microsoft.com/en-us/powershell/module/storage/mount-diskimage?view=windowsserver2022-ps
author: frack113
date: 2022-02-01
tags:
    - attack.defense-impairment
    - attack.t1553.005
logsource:
    product: windows
    category: ps_script
    definition: 'Requirements: Script Block Logging must be enabled'
detection:
    selection:
        ScriptBlockText|contains|all:
            - 'Mount-DiskImage '
            - '-ImagePath '
    condition: selection
falsepositives:
    - Legitimate PowerShell scripts
level: low

Original YAML and metadata in JSON

False positives

• Legitimate PowerShell scripts

Source references

• https://github.com/redcanaryco/atomic-red-team/blob/f339e7da7d05f6057fdfcdd3742bfcf365fee2a9/atomics/T1553.005/T1553.005.md#atomic-test-1---mount-iso-image
• https://learn.microsoft.com/en-us/powershell/module/storage/mount-diskimage?view=windowsserver2022-ps