Disable Windows Event Logging Via Registry

Hunt Hypothesis

Detects tampering with the “Enabled” registry key in order to disable Windows logging of a Windows event channel

Detection Rule

Sigma (Original)

title: Disable Windows Event Logging Via Registry
id: 2f78da12-f7c7-430b-8b19-a28f269b77a3
status: test
description: Detects tampering with the "Enabled" registry key in order to disable Windows logging of a Windows event channel
references:
    - https://twitter.com/WhichbufferArda/status/1543900539280293889
    - https://github.com/DebugPrivilege/CPP/blob/c39d365617dbfbcb01fffad200d52b6239b2918c/Windows%20Defender/RestoreDefenderConfig.cpp
author: frack113, Nasreddine Bencherchali (Nextron Systems)
date: 2022-07-04
modified: 2024-03-25
tags:
    - attack.defense-impairment
    - attack.t1685.001
logsource:
    category: registry_set
    product: windows
detection:
    selection:
        TargetObject|contains: '\Microsoft\Windows\CurrentVersion\WINEVT\Channels\'
        TargetObject|endswith: '\Enabled'
        Details: 'DWORD (0x00000000)'
    filter_main_wevutil:
        Image: 'C:\Windows\system32\wevtutil.exe' # FP generated during installation of manifests via wevtutil
    filter_main_iis:
        Image|startswith: 'C:\Windows\winsxs\'
        Image|endswith: '\TiWorker.exe'  # Many different TargetObjects
    filter_main_svchost:
        Image: 'C:\Windows\System32\svchost.exe'
        TargetObject|contains:
            - '\Microsoft\Windows\CurrentVersion\WINEVT\Channels\Microsoft-Windows-FileInfoMinifilter'
            - '\Microsoft\Windows\CurrentVersion\WINEVT\Channels\Microsoft-Windows-ASN1\'
            - '\Microsoft\Windows\CurrentVersion\WINEVT\Channels\Microsoft-Windows-Kernel-AppCompat\'
            - '\Microsoft\Windows\CurrentVersion\WINEVT\Channels\Microsoft-Windows-Runtime\Error\'
            - '\Microsoft\Windows\CurrentVersion\WINEVT\Channels\Microsoft-Windows-CAPI2/Operational\'
    filter_main_trusted_installer:
        Image: C:\Windows\servicing\TrustedInstaller.exe
        TargetObject|contains: '\Microsoft\Windows\CurrentVersion\WINEVT\Channels\Microsoft-Windows-Compat-Appraiser'
    filter_optional_empty: # This filter is related to aurora. Should be removed when fix is deployed. # TODO: Remove later
        Image: ''
    filter_optional_null: # This filter is related to aurora. Should be removed when fix is deployed. # TODO: Remove later
        Image: null
    condition: selection and not 1 of filter_main_* and not 1 of filter_optional_*
falsepositives:
    - Rare falsepositives may occur from legitimate administrators disabling specific event log for troubleshooting
level: high

KQL (Azure Sentinel)

imRegistry
| where (RegistryKey endswith "\\Microsoft\\Windows\\CurrentVersion\\WINEVT\\Channels*" and RegistryKey endswith "\\Enabled" and RegistryValueData =~ "DWORD (0x00000000)") and (not((ActingProcessName =~ "C:\\Windows\\system32\\wevtutil.exe" or (ActingProcessName startswith "C:\\Windows\\winsxs\\" and ActingProcessName endswith "\\TiWorker.exe") or (ActingProcessName =~ "C:\\Windows\\System32\\svchost.exe" and (RegistryKey contains "\\Microsoft\\Windows\\CurrentVersion\\WINEVT\\Channels\\Microsoft-Windows-FileInfoMinifilter" or RegistryKey endswith "\\Microsoft\\Windows\\CurrentVersion\\WINEVT\\Channels\\Microsoft-Windows-ASN1*" or RegistryKey endswith "\\Microsoft\\Windows\\CurrentVersion\\WINEVT\\Channels\\Microsoft-Windows-Kernel-AppCompat*" or RegistryKey endswith "\\Microsoft\\Windows\\CurrentVersion\\WINEVT\\Channels\\Microsoft-Windows-Runtime\\Error*" or RegistryKey endswith "\\Microsoft\\Windows\\CurrentVersion\\WINEVT\\Channels\\Microsoft-Windows-CAPI2/Operational*")) or (ActingProcessName =~ "C:\\Windows\\servicing\\TrustedInstaller.exe" and RegistryKey contains "\\Microsoft\\Windows\\CurrentVersion\\WINEVT\\Channels\\Microsoft-Windows-Compat-Appraiser")))) and (not((ActingProcessName =~ "" or isnull(ActingProcessName))))

Required Data Sources

False Positive Guidance

• Rare falsepositives may occur from legitimate administrators disabling specific event log for troubleshooting

MITRE ATT&CK Context

• Technique: T1685.001 — T1685.001

References

• https://twitter.com/WhichbufferArda/status/1543900539280293889
• https://github.com/DebugPrivilege/CPP/blob/c39d365617dbfbcb01fffad200d52b6239b2918c/Windows%20Defender/RestoreDefenderConfig.cpp
• SigmaHQ Rule