WevtUtil Usage To Clear Logs
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
Annotations
ATT&CK
Kill Chain Phase
- Exploitation
NIST
- PR.DS
- PR.IP
CIS20
- CIS 8
- CIS 13
CVE
Search
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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:
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 fields
List of fields required to use this analytic.
- _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
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 $dest_device_id$ |
The Risk Score is calculated by the following formula: Risk Score = (Impact * Confidence/100). Initial Confidence and Impact is set by the analytic author.
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
source | version: 2