Bugzilla

(In reply to Robert Strong [:rstrong] (use needinfo to contact me) from comment #25)
> That was a typo in the steps. It should be
> 4.) change the firefox paths in copyloop.bat and mozupdateservicetest.bat to the firefox install location
> 5.) change the path to the update/0 directory in mozupdateservicetest.bat to your path
> 6.) start copyloop.bat (this will overwrite the maintenanceservice.exe in the firefox directory with a test.exe during the update) and mozupdateservicetest.bat (will run the update)
> 
> So copyloop.bat must be started before mozupdateservicetest.bat
> copyloop.bat should have overwritten maintenanceservice.exe in the installation directory which you can verify before running mozupdateservicetest.bat
> 
> Hope this helps.

Yep it does help, thanks! 
I was able to finally reproduce it on a W10 machine, I can see both of the actual results:
> - the test.exe was copied to <mozilla-maintenance-service-directory>/maintenanceservice_tmp.exe.
> - this maintenanceservice_tmp.exe is running as SYSTEM user

I verified that the actual results are not seen on builds that contain the fix (Firefox 69.0 RC, Firefox 68.1.0 esr and Latest Nightly 70.0a1). I'll wait for the official esr60.9 to be built and then I'll verify on it as well.

(In reply to Robert Strong [:rstrong] (use needinfo to contact me) from comment #25)
> That was a typo in the steps. It should be
> 4.) change the firefox paths in copyloop.bat and mozupdateservicetest.bat to the firefox install location
> 5.) change the path to the update/0 directory in mozupdateservicetest.bat to your path
> 6.) start copyloop.bat (this will overwrite the maintenanceservice.exe in the firefox directory with a test.exe during the update) and mozupdateservicetest.bat (will run the update)
> 
> So copyloop.bat must be started before mozupdateservicetest.bat
> copyloop.bat should have overwritten maintenanceservice.exe in the installation directory which you can verify before running mozupdateservicetest.bat
> 
> Hope this helps.

Yep it does help, thanks! 
I was able to finally reproduce it on a W10 machine, I can see both of the actual results on an affected build (68.0.2):
> - the test.exe was copied to <mozilla-maintenance-service-directory>/maintenanceservice_tmp.exe.
> - this maintenanceservice_tmp.exe is running as SYSTEM user

I verified that the actual results are not seen on builds that contain the fix (Firefox 69.0 RC, Firefox 68.1.0 esr and Latest Nightly 70.0a1). I'll wait for the official esr60.9 to be built and then I'll verify on it as well.