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Description

The wevtutil.exe application is the windows event log utility. This searches for wevtutil.exe with parameters for clearing the application, security, setup, powershell, sysmon, or system event logs.

  • Type: TTP
  • Product: Splunk Behavioral Analytics
  • Datamodel: Endpoint_Processes
  • Last Updated: 2021-06-15
  • Author: Teoderick Contreras, Splunk
  • ID: 5438113c-cdd9-11eb-93b8-acde48001122

ATT&CK

ID Technique Tactic
T1070 Indicator Removal on Host Defense Evasion
T1070.001 Clear Windows Event Logs Defense Evasion
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| from read_ssa_enriched_events() 
| where "Endpoint_Processes" IN(_datamodels) 
| eval timestamp=parse_long(ucast(map_get(input_event, "_time"), "string", null)), cmd_line=ucast(map_get(input_event, "process"), "string", null), process_name=ucast(map_get(input_event, "process_name"), "string", null), process_path=ucast(map_get(input_event, "process_path"), "string", null), parent_process_name=ucast(map_get(input_event, "parent_process_name"), "string", null), event_id=ucast(map_get(input_event, "event_id"), "string", null) 
| where cmd_line IS NOT NULL AND like(cmd_line, "% cl %") AND (match_regex(cmd_line, /(?i)security/)=true OR match_regex(cmd_line, /(?i)system/)=true OR match_regex(cmd_line, /(?i)sysmon/)=true OR match_regex(cmd_line, /(?i)application/)=true OR match_regex(cmd_line, /(?i)setup/)=true OR match_regex(cmd_line, /(?i)powershell/)=true) AND process_name="wevtutil.exe" 
| eval start_time=timestamp, end_time=timestamp, entities=mvappend(ucast(map_get(input_event, "dest_user_id"), "string", null), ucast(map_get(input_event, "dest_device_id"), "string", null)) 
| eval body=create_map(["event_id", event_id, "cmd_line", cmd_line, "process_name", process_name, "parent_process_name", parent_process_name, "process_path", process_path]) 
| into write_ssa_detected_events();

Macros

The SPL above uses the following Macros:

Note that wevtutil_usage_to_clear_logs_filter is a empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.

Required field

  • _time
  • dest_device_id
  • process_name
  • parent_process_name
  • process_path
  • dest_user_id
  • process

How To Implement

You must be ingesting data that records process activity from your hosts to populate the Endpoint data model in the Processes node. You must also be ingesting logs with both the process name and command line from your endpoints. The command-line arguments are mapped to the "process" field in the Endpoint data model.

Known False Positives

The wevtutil.exe application is a legitimate Windows event log utility. Administrators may use it to manage Windows event logs.

Associated Analytic story

Kill Chain Phase

  • Exploitation

RBA

Risk Score Impact Confidence Message
63.0 70 90 A wevtutil process $process_name$ with commandline $cmd_line$ to clear event logs in host $dest_device_id$

Note that risk score is calculated base on the following formula: (Impact * Confidence)/100

Reference

Test Dataset

Replay any dataset to Splunk Enterprise by using our replay.py tool or the UI. Alternatively you can replay a dataset into a Splunk Attack Range

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