Adversaries may disable Windows event logging to limit data that can be leveraged for detections and audits. Windows event logs record user and system activity such as login attempts, process creation, and much more. This data is used by security tools and analysts to generate detections.
The EventLog service maintains event logs from various system components and applications. By default, the service automatically starts when a system powers on. An audit policy, maintained by the Local Security Policy (secpol.msc), defines which system events the EventLog service logs. Security audit policy settings can be changed by running secpol.msc, then navigating to
Security Settings\Local Policies\Audit Policy for basic audit policy settings or
Security Settings\Advanced Audit Policy Configuration for advanced audit policy settings.
auditpol.exe may also be used to set audit policies.
Adversaries may target system-wide logging or just that of a particular application. For example, the EventLog service may be disabled using the following PowerShell line:
Stop-Service -Name EventLog. Additionally, adversaries may use
auditpol and its sub-commands in a command prompt to disable auditing or clear the audit policy. To enable or disable a specified setting or audit category, adversaries may use the
/failure parameters. For example,
auditpol /set /category:"Account Logon" /success:disable /failure:disable turns off auditing for the Account Logon category. To clear the audit policy, adversaries may run the following lines:
auditpol /clear /y or
auditpol /remove /allusers.
By disabling Windows event logging, adversaries can operate while leaving less evidence of a compromise behind.
Consider periodic review of
|M1022||Restrict File and Directory Permissions||
Ensure proper process and file permissions are in place to prevent adversaries from disabling or interfering with logging or deleting or modifying .evtx logging files. Ensure .evtx files, which are located at
|M1024||Restrict Registry Permissions||
Ensure proper Registry permissions are in place to prevent adversaries from disabling or interfering logging. The addition of the MiniNT registry key disables Event Viewer.
|M1018||User Account Management||
Ensure proper user permissions are in place to prevent adversaries from disabling or interfering with logging.
|ID||Data Source||Data Component|
|DS0015||Application Log||Application Log Content|
|DS0013||Sensor Health||Host Status|
|DS0024||Windows Registry||Windows Registry Key Creation|
Monitor processes and command-line arguments for commands that can be used to disable logging. For example, Wevtutil,
sc stop EventLog, and offensive tooling (such as Mimikatz and
Invoke-Phant0m) may be used to clear logs.
In Event Viewer, Event ID 1102 under the "Security" Windows Log and Event ID 104 under the "System" Windows Log both indicate logs have been cleared.
Service Control Manager Event ID 7035 in Event Viewer may indicate the termination of the EventLog service. Additionally, gaps in the logs, e.g. non-sequential Event Record IDs, may indicate that the logs may have been tampered.
Monitor the addition of the MiniNT registry key in
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control, which may disable Event Viewer.