Unload Sysmon Filter Driver
Description
Attackers often disable security tools to avoid detection. This search looks for the usage of process fltMC.exe
to unload a Sysmon Driver that will stop sysmon from collecting the data.
- Type: TTP
- Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
- Datamodel: Endpoint- Datasource: Splunk Add-on for Sysmon
- Last Updated: 2020-07-22
- Author: Bhavin Patel, Splunk
- ID: e5928ff3-23eb-4d8b-b8a4-dcbc844fdfbe
Annotations
ATT&CK
Kill Chain Phase
- Actions on Objectives
NIST
- DE.CM
CIS20
- CIS 8
CVE
Search
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| tstats `security_content_summariesonly` count min(_time) as firstTime values(Processes.process) as process max(_time) as lastTime from datamodel=Endpoint.Processes where Processes.process_name=fltMC.exe AND Processes.process=*unload* AND Processes.process=*SysmonDrv* by Processes.process_name Processes.process_id Processes.parent_process_name Processes.process Processes.dest Processes.user
| `drop_dm_object_name("Processes")`
| `security_content_ctime(firstTime)`
|`security_content_ctime(lastTime)`
|`unload_sysmon_filter_driver_filter`
| table firstTime lastTime dest user count process_name process_id parent_process_name process
Macros
The SPL above uses the following Macros:
Note that unload_sysmon_filter_driver_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
- Processes.process_name
- Processes.process
- Processes.process_id
- Processes.parent_process_name
- Processes.dest
- Processes.user
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. This search is also shipped with unload_sysmon_filter_driver_filter
macro, update this macro to filter out false positives.
Known False Positives
Associated Analytic story
RBA
Risk Score | Impact | Confidence | Message |
---|---|---|---|
45.0 | 50 | 90 | Possible Sysmon filter driver unloading on $dest$ |
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: 3