splunk-security_content/docs/_posts/2022-01-28-disabling_defender_services.md

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Disabling Defender Services	Disable or Modify Tools , Impair Defenses	Endpoint	2022-01-28	true		Disable or Modify Tools Impair Defenses Defense Evasion Defense Evasion Splunk Enterprise Splunk Enterprise Security Splunk Cloud Endpoint

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Description

This particular behavior is typically executed when an adversaries or malware gains access to an endpoint and beings to perform execution and to evade detections. Usually, a batch (.bat) will be executed and multiple registry and scheduled task modifications will occur. During triage, review parallel processes and identify any further file modifications. Endpoint should be isolated.

• Type: TTP
• Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
• Datamodel: Endpoint- Datasource: Splunk Add-on for Sysmon
• Last Updated: 2022-01-28
• Author: Teoderick Contreras, Splunk
• ID: 911eacdc-317f-11ec-ad30-acde48001122

Annotations

ATT&CK

ID	Technique	Tactic
T1562.001	Disable or Modify Tools	Defense Evasion

| T1562 | Impair Defenses | Defense Evasion |

Kill Chain Phase

• Exploitation

NIST

CIS20

CVE

Search

| tstats `security_content_summariesonly` count from datamodel=Endpoint.Registry where Registry.registry_path = "*\\System\\CurrentControlSet\\Services\\*" AND (Registry.registry_path IN("*WdBoot*", "*WdFilter*", "*WdNisDrv*", "*WdNisSvc*","*WinDefend*", "*SecurityHealthService*")) AND Registry.registry_value_name = Start Registry.registry_value_data = 0x00000004 by _time span=1h Registry.dest Registry.user Registry.registry_path Registry.registry_value_name Registry.registry_value_data Registry.process_guid 
| `drop_dm_object_name(Registry)` 
|rename process_guid as proc_guid 
|join proc_guid, _time [
| tstats `security_content_summariesonly` count FROM datamodel=Endpoint.Processes by _time span=1h Processes.process_id Processes.process_name Processes.process Processes.dest Processes.parent_process_name Processes.parent_process Processes.process_guid 
| `drop_dm_object_name(Processes)` 
|rename process_guid as proc_guid 
| fields _time dest user parent_process_name parent_process process_name process_path process proc_guid registry_path registry_value_name registry_value_data] 
| table _time dest user parent_process_name parent_process process_name process_path process proc_guid registry_path registry_value_name registry_value_data 
| `disabling_defender_services_filter`

Macros

The SPL above uses the following Macros:

• security_content_summariesonly

ℹ️ disabling_defender_services_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
• Registry.dest
• Registry.user
• Registry.registry_value_name
• Registry.registry_key_name
• Registry.registry_path
• Registry.registry_value_data

How To Implement

To successfully implement this search, you need to be ingesting logs with the process name, parent process, and command-line executions from your endpoints. If you are using Sysmon, you must have at least version 6.0.4 of the Sysmon TA.

Known False Positives

admin or user may choose to disable windows defender product

Associated Analytic story

• IceID
• Windows Registry Abuse

RBA

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

ℹ️ 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

• https://thedfirreport.com/2021/10/18/icedid-to-xinglocker-ransomware-in-24-hours/

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

• https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/malware/icedid/disable_av/sysmon2.log

source | version: 2