Windows Eventlog Cleared Via Wevtutil
Description
The following analytic detects the usage of wevtutil.exe with the "clear-log" parameter in order to clear the contents of logs. Clearing the event logs can be an attempt to cover tracks after malicious actions, hindering forensic investigations.
Query · spl
| tstats `security_content_summariesonly`
count values(Processes.process) as process
min(_time) as firstTime
max(_time) as lastTime
FROM datamodel=Endpoint.Processes WHERE
Processes.process_name=wevtutil.exe
Processes.process IN ("* cl *", "*clear-log*")
```
We exclude the following strings to avoid detection overlap and double coverage since they are already covered by the "Suspicious wevtutil Usage" detection.
```
NOT Processes.process IN (
"*/Trace*",
"*AMSI/Debug*",
"*Application*",
"*CiscoSecureEndpoint*",
"*Microsoft-Windows-BitLocker*",
"*Microsoft-Windows-Bits*",
"*Microsoft-Windows-CAPI2*",
"*Microsoft-Windows-Kernel-File*",
"*Microsoft-Windows-Kernel-Process*",
"*Microsoft-Windows-LDAP*",
"*Microsoft-Windows-PowerShell*",
"*Microsoft-Windows-Sysmon*",
"*Microsoft-Windows-TerminalServices-LocalSessionManager*",
"*Microsoft-Windows-TerminalServices-RemoteConnectionManager*",
"*Microsoft-Windows-WMI-Activity*",
"*OpenSSH/*",
"*PowerShellCore/*",
"*Security*",
"*Setup*",
"*System*",
"*Windows Firewall With Advanced Security*",
"*Windows PowerShell*"
)
BY Processes.action Processes.dest Processes.original_file_name
Processes.parent_process Processes.parent_process_exec Processes.parent_process_guid
Processes.parent_process_id Processes.parent_process_name Processes.parent_process_path
Processes.process Processes.process_exec Processes.process_guid
Processes.process_hash Processes.process_id Processes.process_integrity_level
Processes.process_name Processes.process_path Processes.user
Processes.user_id Processes.vendor_product
| `drop_dm_object_name(Processes)`
| `security_content_ctime(firstTime)`
| `security_content_ctime(lastTime)`
| `windows_eventlog_cleared_via_wevtutil_filter`
Implementation guide
The detection is based on data that originates from Endpoint Detection and Response (EDR) agents. These agents are designed to provide security-related telemetry from the endpoints where the agent is installed. To implement this search, you must ingest logs that contain the process GUID, process name, and parent process. Additionally, you must ingest complete command-line executions. These logs must be processed using the appropriate Splunk Technology Add-ons that are specific to the EDR product. The logs must also be mapped to the Processes node of the Endpoint data model. Use the Splunk Common Information Model (CIM) to normalize the field names and speed up the data modeling process.
Known false positives
- The wevtutil.exe application is a legitimate Windows event log utility. Administrators may use it to manage Windows event logs.
Analyst notes
Known false positives: The wevtutil.exe application is a legitimate Windows event log utility. Administrators may use it to manage Windows event logs.