Sigma rule: Windows Event Log Access Tampering Via Registry

Rule

Title

Windows Event Log Access Tampering Via Registry

Status

experimental

Level

high

Author

X__Junior

Date

2025-01-16

Modified

2025-08-16

File

rules/windows/registry/registry_set/registry_set_disable_windows_event_log_access.yml

Commit

ccbb0369507f796db0b0ae6854c8a2be471b9d84

Detects changes to the Windows EventLog channel permission values. It focuses on changes to the Security Descriptor Definition Language (SDDL) string, as modifications to these values can restrict access to specific users or groups, potentially aiding in defense evasion by controlling who can view or modify a event log channel. Upon execution, the user shouldn't be able to access the event log channel via the event viewer or via utilities such as "Get-EventLog" or "wevtutil".

Log source

product

windows

category

registry_set

Detection

# O:SYG:SYD:(D;;0x1;;;WD)
# O:BAG:SYD:(A;;0x2;;;S-1-15-2-1)(D;;0x1;;;WD)
selection_key_1:
    TargetObject|contains: '\SYSTEM\CurrentControlSet\Services\EventLog\'
    TargetObject|endswith: '\CustomSD'
selection_key_2:
    TargetObject|contains:
        - '\Policies\Microsoft\Windows\EventLog\'
        - '\Microsoft\Windows\CurrentVersion\WINEVT\Channels'
    TargetObject|endswith: '\ChannelAccess'
selection_details:
    - Details|contains: 'D:(D;'
    - Details|contains|all:
          - 'D:('
          - ')(D;'
filter_main_trustedinstaller:
    Image: 'C:\Windows\servicing\TrustedInstaller.exe'
filter_main_tiworker:
    Image|startswith: 'C:\Windows\WinSxS\'
    Image|endswith: '\TiWorker.exe'
filter_optional_empty:
    Image: ''
filter_optional_null:
    Image: null
condition: 1 of selection_key_* and selection_details and not 1 of filter_main_* and not 1 of filter_optional_*

False positives (as the rule lists them)

• Administrative activity, still unlikely

Tags

• attack.privilege-escalation
• attack.persistence
• attack.defense-impairment
• attack.t1547.001
• attack.t1112

MITRE ATT&CK ids this rule names

• T1112
• T1547.001

References

• https://www.atomicredteam.io/atomic-red-team/atomics/T1562.002#atomic-test-8---modify-event-log-channel-access-permissions-via-registry---powershell
• https://www.youtube.com/watch?v=uSYvHUVU8xY
• https://learn.microsoft.com/en-us/windows/win32/secauthz/security-descriptor-definition-language

Read on 2026-11-03T00:58:21.399Z under licence sigma-drl-1.1@d5f4c36a from https://github.com/SigmaHQ/sigma/blob/ccbb0369507f796db0b0ae6854c8a2be471b9d84/rules/windows/registry/registry_set/registry_set_disable_windows_event_log_access.yml