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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
ID Technique Tactic
T1562.001 Disable or Modify Tools Defense Evasion
T1562 Impair Defenses Defense Evasion
Kill Chain Phase
  • Actions on Objectives
NIST
  • DE.CM
CIS20
  • CIS 8
CVE 
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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