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Description

The following analytic detects the modification of the Windows Defender MpEngine registry value, specifically setting MpEnablePus to 0x00000000. This detection leverages endpoint registry logs, focusing on changes within the path "\Policies\Microsoft\Windows Defender\MpEngine". This activity is significant as it indicates an attempt to disable key Windows Defender features, potentially allowing malware to evade detection. If confirmed malicious, this could lead to undetected malware execution, persistence, and further system compromise. Immediate investigation and endpoint isolation are recommended.

  • Type: TTP
  • Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
  • Datamodel: Endpoint
  • Last Updated: 2024-05-21
  • Author: Steven Dick, Teoderick Contreras, Splunk
  • ID: cc391750-3024-11ec-955a-acde48001122

Annotations

ATT&CK

ATT&CK

ID Technique Tactic
T1562.001 Disable or Modify Tools Defense Evasion
T1562 Impair Defenses Defense Evasion
Kill Chain Phase
  • Exploitation
NIST
  • DE.CM
CIS20
  • CIS 10
CVE 


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| tstats `security_content_summariesonly` count FROM datamodel=Endpoint.Registry WHERE (Registry.registry_path = "*\\Policies\\Microsoft\\Windows Defender\\MpEngine*" Registry.registry_value_name = MpEnablePus Registry.registry_value_data = 0x00000000) BY _time span=1h Registry.registry_path Registry.registry_key_name Registry.registry_value_name Registry.registry_value_data Registry.process_guid Registry.user Registry.dest 
| `drop_dm_object_name(Registry)` 
| where isnotnull(registry_value_data) 
| `security_content_ctime(firstTime)` 
| `security_content_ctime(lastTime)` 
| `disable_defender_mpengine_registry_filter`

Macros

The SPL above uses the following Macros:

:information_source: disable_defender_mpengine_registry_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
  • Registry.dest
  • Registry.registry_value_name
  • Registry.registry_key_name
  • Registry.registry_path
  • Registry.registry_value_data
  • Registry.process_guid

How To Implement

To successfully implement this search, you need to be ingesting logs with the registry value name, registry path, and registry value data from your endpoints. If you are using Sysmon, you must have at least version 2.0 of the offical Sysmon TA. https://splunkbase.splunk.com/app/5709

Known False Positives

admin or user may choose to disable windows defender product

Associated Analytic Story

RBA

Risk Score Impact Confidence Message
49.0 70 70 Modified/added/deleted registry entry $registry_path$ in $dest$

:information_source: 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: 5