Detection rules › Sigma

Windows Defender Exploit Guard Tamper

Status
test
Severity
high
Log source
product windows, service windefend
Author
Nasreddine Bencherchali (Nextron Systems)
Source
github.com/SigmaHQ/sigma

Detects when someone is adding or removing applications or folders from exploit guard "ProtectedFolders" or "AllowedApplications"

MITRE ATT&CK coverage

TacticTechniques
Defense ImpairmentT1685 Disable or Modify Tools

Event coverage

Rule body yaml

title: Windows Defender Exploit Guard Tamper
id: a3ab73f1-bd46-4319-8f06-4b20d0617886
status: test
description: |
    Detects when someone is adding or removing applications or folders from exploit guard "ProtectedFolders" or "AllowedApplications"
references:
    - https://techcommunity.microsoft.com/t5/core-infrastructure-and-security/windows-10-controlled-folder-access-event-search/ba-p/2326088
author: Nasreddine Bencherchali (Nextron Systems)
date: 2022-08-05
modified: 2022-12-06
tags:
    - attack.defense-impairment
    - attack.t1685
logsource:
    product: windows
    service: windefend
detection:
    allowed_apps_key:
        EventID: 5007 # The antimalware platform configuration changed.
        NewValue|contains: '\Windows Defender\Windows Defender Exploit Guard\Controlled Folder Access\AllowedApplications\'
    allowed_apps_path:
        NewValue|contains:
            # Add more paths you don't allow in your org
            - '\Users\Public\'
            - '\AppData\Local\Temp\'
            - '\Desktop\'
            - '\PerfLogs\'
            - '\Windows\Temp\'
    protected_folders:
        EventID: 5007 # The antimalware platform configuration changed.
        # This will trigger on any folder removal. If you experience FP's then add another selection with specific paths
        OldValue|contains: '\Windows Defender\Windows Defender Exploit Guard\Controlled Folder Access\ProtectedFolders\'
    condition: all of allowed_apps* or protected_folders
falsepositives:
    - Unlikely
level: high

Stages and Predicates

Stage 0: condition

all of allowed_apps* or protected_folders

Stage 1: allowed_apps_key

allowed_apps_key:
    EventID: 5007
    NewValue|contains: '\Windows Defender\Windows Defender Exploit Guard\Controlled Folder Access\AllowedApplications\'

Stage 2: allowed_apps_path

allowed_apps_path:
    NewValue|contains:
        - '\Users\Public\'
        - '\AppData\Local\Temp\'
        - '\Desktop\'
        - '\PerfLogs\'
        - '\Windows\Temp\'

Stage 3: protected_folders

protected_folders:
    EventID: 5007
    OldValue|contains: '\Windows Defender\Windows Defender Exploit Guard\Controlled Folder Access\ProtectedFolders\'

Indicators

Each row is a field, operator, and value that the rule matches. The corpus column counts how many other rules in the catalog look for the same combination: high numbers point to widely-used, community-vetted indicators. Blank or 1 shows that the indicator is specific to this rule.

FieldKindValues
NewValuematch
  • \AppData\Local\Temp\ corpus 8 (sigma 8)
  • \Desktop\ corpus 3 (sigma 3)
  • \PerfLogs\ corpus 3 (sigma 3)
  • \Users\Public\ corpus 5 (sigma 5)
  • \Windows Defender\Windows Defender Exploit Guard\Controlled Folder Access\AllowedApplications\
  • \Windows\Temp\ corpus 5 (sigma 5)
OldValuematch
  • \Windows Defender\Windows Defender Exploit Guard\Controlled Folder Access\ProtectedFolders\