[wix-users] Deferred CustomAction in System context get access denied

[Ilir Bekteshi]

I'm having some problems with privileges when running a CustomAction in
deferred mode.

I want to kill some Service processes which could be running using
different user accounts from Local System to regular users, but the CA
succeeds only when the processes and the CA are executed as the same user.
Here are some cases and results:

"process1.exe" is a process running as the same user running the
installation. If the kill CA is run in System context using
Impersonate="no" the access is denied.
"process1.exe" is a process running as the same user running the
installation. If the kill CA is run in User context using Impersonate="yes"
the process is killed.

"process1.exe" is a process running as another user. If the kill CA is run
in User context using Impersonate="yes" the access is denied.
"process1.exe" is a process running as another user. If the kill CA is run
in System context using Impersonate="no" the access is denied

"process1.exe" is a process running as Local System. If the kill CA is run
in User context using Impersonate="yes" the access is denied.
"process1.exe" is a process running as Local System. If the kill CA is run
in System context using Impersonate="no" the process is killed.

<SetProperty Id="KillUserProcess"
Value='"[WindowsFolder]\System32\taskkill.exe" /F /IM process1.exe'
After="CostFinalize" />
<CustomAction Id="KillUserProcess" BinaryKey="WixCA" DllEntry="CAQuietExec"
Execute="deferred" Impersonate="no" Return="check" />

<SetProperty Id="KillSysProcess"
Value='"[WindowsFolder]\System32\taskkill.exe" /F /IM process2.exe'
After="CostFinalize" />
<CustomAction Id="KillSysProcess" BinaryKey="WixCA" DllEntry="CAQuietExec"
Execute="deferred" Impersonate="no" Return="check" />

<InstallExecuteSequence>
<Custom Action="KillUserProcess" After="InstallInitialize"></Custom>
<Custom Action="KillSysProcess" After="KillUserProcess"></Custom>
</InstallExecuteSequence>

Action=KillUserProcess,ActionType=3137,Source=BinaryData,Target=CAQuietExec,CustomActionData="C:\Windows\System32\taskkill.exe"
/F /IM process1.exe)
CAQuietExec:  "C:\Windows\System32\taskkill.exe" /F /IM process1.exe
CAQuietExec:  ERROR: The process "process1.exe" with PID 3164 could not be
terminated.
CAQuietExec:  Reason: Access is denied.
CAQuietExec:
CAQuietExec:  Error 0x80070001: Command line returned an error.
CAQuietExec:  Error 0x80070001: QuietExec Failed
CAQuietExec:  Error 0x80070001: Failed in ExecCommon method

Action=KillSysProcess,ActionType=3137,Source=BinaryData,Target=CAQuietExec,CustomActionData="C:\Windows\System32\taskkill.exe"
/F /IM process2.exe)
CAQuietExec:  "C:\Windows\System32\taskkill.exe" /F /IM process2.exe
CAQuietExec:  SUCCESS: The process "process2.exe" with PID 4596 has been
terminated.


If LocalSystem doesn't have the rights to kill the processes, who does?
Running these commands from Command Prompt work without problem when
elevated.
Even using psexec from SysInternal to run the command as System work
without a problem. Only when running through MSI are these issues faced.

Is it possible to make a Custom Action running as a System kill processes
not owned only by System?