ISO Image Mounted — Sigma Rule

Rule metadata and linked tags

Author: Syed Hasan (@syedhasan009). Source status: test; severity: medium. Source dates: 2021-05-29 / 2023-11-09.

{
  "product": "windows",
  "service": "security",
  "definition": "The advanced audit policy setting \"Object Access > Audit Removable Storage\" must be configured for Success/Failure"
}

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: 92232cd163ff4be6e9ef79b5b107940be52aa0cb51e001d494799e8645df2684

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: ISO Image Mounted
id: 0248a7bc-8a9a-4cd8-a57e-3ae8e073a073
status: test
description: Detects the mount of an ISO image on an endpoint
references:
    - https://www.trendmicro.com/vinfo/hk-en/security/news/cybercrime-and-digital-threats/malicious-spam-campaign-uses-iso-image-files-to-deliver-lokibot-and-nanocore
    - https://www.proofpoint.com/us/blog/threat-insight/threat-actor-profile-ta2719-uses-colorful-lures-deliver-rats-local-languages
    - https://twitter.com/MsftSecIntel/status/1257324139515269121
    - https://github.com/redcanaryco/atomic-red-team/blob/0f229c0e42bfe7ca736a14023836d65baa941ed2/atomics/T1553.005/T1553.005.md#atomic-test-1---mount-iso-image
author: Syed Hasan (@syedhasan009)
date: 2021-05-29
modified: 2023-11-09
tags:
    - attack.initial-access
    - attack.t1566.001
logsource:
    product: windows
    service: security
    definition: 'The advanced audit policy setting "Object Access > Audit Removable Storage" must be configured for Success/Failure'
detection:
    selection:
        EventID: 4663
        ObjectServer: 'Security'
        ObjectType: 'File'
        ObjectName|startswith: '\Device\CdRom'
    filter_main_generic:
        ObjectName:
            - '\Device\CdRom0\autorun.ico'
            - '\Device\CdRom0\setup.exe'
            - '\Device\CdRom0\setup64.exe'
    condition: selection and not 1 of filter_main_*
falsepositives:
    - Software installation ISO files
level: medium

Original YAML and metadata in JSON

False positives

• Software installation ISO files

Source references

• https://www.trendmicro.com/vinfo/hk-en/security/news/cybercrime-and-digital-threats/malicious-spam-campaign-uses-iso-image-files-to-deliver-lokibot-and-nanocore
• https://www.proofpoint.com/us/blog/threat-insight/threat-actor-profile-ta2719-uses-colorful-lures-deliver-rats-local-languages
• https://twitter.com/MsftSecIntel/status/1257324139515269121
• https://github.com/redcanaryco/atomic-red-team/blob/0f229c0e42bfe7ca736a14023836d65baa941ed2/atomics/T1553.005/T1553.005.md#atomic-test-1---mount-iso-image