Tag Archive: Tamper protection

SEC-LABS R&D > Tamper protection

Tamper Protection for Exclusions in Defender

2023-02-04 0 Comments

One thing that threat actors commonly do when getting a foothold on a device, is to try to disable Defender services and adding exclusions for their tools which they plan to execute.

For the Defender services, we have had Tamper Protection for some time, but that did not cover exclusions.

Tamper Protection configuration via Intune

Requirements

For Tamper Protection to cover exclusions, the following requirements must be met:

Disable Local Admin Merge

Verifying and troubleshooting

The registry value TPExclusions which is in the HKLM\SOFTWARE\Microsoft\Windows Defender\Features key shows a value of 1 if protected and 0 if not protected. Please note that you cannot change the registry value to protect the exclusions, it’s for information and not configuration

While we talk about Antivirus policies…

We would like to share this as well since it’s something we see when we do Defender assessments, it’s unfortunately very common that these settings are wrong

Cloud block level (high is recommended minimum) and Cloud Extended Timeout check must be set to 50 (seconds)
Sample submission is required for Cloud protection

And for

Happy Hunting!

Detect, Protect, Security

, , ,

Defender troubleshooting mode

2022-05-28 0 Comments

Troubleshooting mode will make it possible for local admins on the endpoint to override Antivirus policy on the device, including tamper protection. When enabled it give the admin a 3 hour window to do what was intended. After the 3 hour window, the settings will be re-applied again.

Enabling Troubleshooting mode

Go to the Device page in Microsoft 365 Defender and click on the 3 dots menu item and select troubleshooting mode

In the Device action center we can see the following entry

Prerequisites

  • Windows 10 (version 19044.1618 and above)
    Windows 11
    Windows Server 2019
    Windows Server 2022
  • Microsoft Defender for Endpoint must be tenant-enrolled and active on the device. 
  • The device must be actively running Microsoft Defender Antivirus, version 4.18.2203 and above. 

Hunting for events

//Use the following ActionType and the DeviceEvents table
DeviceEvents
| where ActionType == "AntivirusTroubleshootModeEvent"

Happy Hunting!

Detect, Protect, Respond, Security

, ,