splApache-2.0from splunk/security_content

Unload Sysmon Filter Driver

The following analytic detects the use of `fltMC.exe` to unload the Sysmon driver, which stops Sysmon from collecting data. It leverages Endpoint Detection and Response (EDR) logs, focusing on process names and command-line executions. This activity is significant because disabling Sysmon can blind security monitoring, allowing malicious actions to go undetected. If confirmed malicious, this could enable attackers to execute further attacks without being logged, leading to potential data breaches, privilege escalation, or persistent access within the environment.

Quality

FP risk

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Rule sourcedetections/endpoint/unload_sysmon_filter_driver.yml

| 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.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)`
| table firstTime lastTime dest user count process_name process_id parent_process_name process
| `unload_sysmon_filter_driver_filter`