Windows Registry: Exploit Guard ProtectedFolders Value Deleted

Alerts on deletion of registry values under Exploit Guard Controlled Folder Access ProtectedFolders.

FreeUnreviewedSigmahighv1

windows-registry-exploit-guard-protectedfolders-value-deleted-272e55a4

title: "Windows Registry: Exploit Guard ProtectedFolders Value Deleted"
id: f931145c-1c7f-4097-879c-8f2a58ea0b6b
status: test
description: This rule flags registry value deletions where the TargetObject path contains the Windows Defender Exploit Guard Controlled Folder Access ProtectedFolders list. Removing entries from this list can reduce protection for selected folders, potentially enabling processes an attacker wants to run. It relies on Windows Registry delete-value events (EventType=DeleteValue) with the affected TargetObject containing the ProtectedFolders registry location.
references:
  - https://www.microsoft.com/security/blog/2017/10/23/windows-defender-exploit-guard-reduce-the-attack-surface-against-next-generation-malware/
  - https://github.com/SigmaHQ/sigma/blob/master/rules/windows/registry/registry_delete/registry_delete_exploit_guard_protected_folders.yml
author: Nasreddine Bencherchali (Nextron Systems), Huntrule Team
date: 2022-08-05
modified: 2023-02-08
tags:
  - attack.defense-impairment
  - attack.t1685
logsource:
  category: registry_delete
  product: windows
detection:
  selection:
    EventType: DeleteValue
    TargetObject|contains: SOFTWARE\Microsoft\Windows Defender\Windows Defender Exploit Guard\Controlled Folder Access\ProtectedFolders
  condition: selection
falsepositives:
  - Legitimate administrators removing applications (should always be investigated)
level: high
license: DRL-1.1
related:
  - id: 272e55a4-9e6b-4211-acb6-78f51f0b1b40
    type: derived

What it detects

This rule flags registry value deletions where the TargetObject path contains the Windows Defender Exploit Guard Controlled Folder Access ProtectedFolders list. Removing entries from this list can reduce protection for selected folders, potentially enabling processes an attacker wants to run. It relies on Windows Registry delete-value events (EventType=DeleteValue) with the affected TargetObject containing the ProtectedFolders registry location.

Known false positives

Legitimate administrators removing applications (should always be investigated)

Detection content is published as a reviewed draft. Tune thresholds and exclusions against your own telemetry before enabling this rule for alerting.