Even though Defender has a lot of fancy defensive features such as tamper protection, it can still be disabled with the following chain of actions:

1. enable SeDebugPrivilege;
2. start the TrustedInstaller service and TrustedInstaller process;
3. impersonate TrustedInstaller;
4. open the WinDefend service and stop it;

DefenderSwitch does exactly that through the use of the Win32 API.

DefenderSwitch uses the standard Windows.h header and the WIL library. To install WIL use vcpkg:

C:\vcpkg> .\vcpkg.exe install wil:x86-windows
C:\vcpkg> .\vcpkg.exe install wil:x64-windows

Spawn a cmd.exe as administrator, then:

C:\Users\last> .\DefenderSwitch.exe -off
C:\Users\last> .\DefenderSwitch.exe -on

This tool as it is written is definetely not OPSEC safe. Making it so is left as an exercise to the user :)