Bypass UAC Using Event Viewer

Hunt Hypothesis

Bypasses User Account Control using Event Viewer and a relevant Windows Registry modification

Detection Rule

Sigma (Original)

title: Bypass UAC Using Event Viewer
id: 674202d0-b22a-4af4-ae5f-2eda1f3da1af
status: test
description: Bypasses User Account Control using Event Viewer and a relevant Windows Registry modification
references:
    - https://enigma0x3.net/2016/08/15/fileless-uac-bypass-using-eventvwr-exe-and-registry-hijacking/
    - https://github.com/redcanaryco/atomic-red-team/blob/f339e7da7d05f6057fdfcdd3742bfcf365fee2a9/atomics/T1548.002/T1548.002.md#atomic-test-1---bypass-uac-using-event-viewer-cmd
author: frack113
date: 2022-01-05
modified: 2023-08-17
tags:
    - attack.privilege-escalation
    - attack.persistence
    - attack.t1547.010
logsource:
    category: registry_set
    product: windows
detection:
    selection:
        TargetObject|endswith: '_Classes\mscfile\shell\open\command\(Default)'
    filter:
        Details|startswith: '%SystemRoot%\system32\mmc.exe "%1" %'
    condition: selection and not filter
falsepositives:
    - Unknown
level: high
regression_tests_path: regression_data/rules/windows/registry/registry_set/registry_set_bypass_uac_using_eventviewer/info.yml
simulation:
    - type: atomic-red-team
      name: Bypass UAC using Event Viewer (cmd)
      technique: T1548.002
      atomic_guid: 5073adf8-9a50-4bd9-b298-a9bd2ead8af9

KQL (Azure Sentinel)

imRegistry
| where RegistryKey endswith "_Classes\\mscfile\\shell\\open\\command\\(Default)" and (not(RegistryValueData startswith "%SystemRoot%\\system32\\mmc.exe \"%1\" %"))

KQL (Microsoft 365 Defender)

DeviceRegistryEvents
| where RegistryKey endswith "_Classes\\mscfile\\shell\\open\\command\\(Default)" and (not(RegistryValueData startswith "%SystemRoot%\\system32\\mmc.exe \"%1\" %"))

Required Data Sources

False Positive Guidance

• Unknown

MITRE ATT&CK Context

• Tactic: Privilege Escalation
• Tactic: Persistence
• Technique: T1547.010 — T1547.010

References

• https://enigma0x3.net/2016/08/15/fileless-uac-bypass-using-eventvwr-exe-and-registry-hijacking/
• https://github.com/redcanaryco/atomic-red-team/blob/f339e7da7d05f6057fdfcdd3742bfcf365fee2a9/atomics/T1548.002/T1548.002.md#atomic-test-1---bypass-uac-using-event-viewer-cmd
• SigmaHQ Rule