Setting Registry from windows service does not work-CodePudding

I am setting or reading reg key from a windows services which runs as local system. But when I read or set the values in the Registry Editor they are not the same as when i read and set them from the windows services.

If I execute the following command in powershell from the windows services or when i am logged in as a user the results differ as well. Why? Is there a different LocalMachine for a LocalSystem account?

$DefaultUserName = (Get-ItemProperty -Path "HKLM:\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon" -Name "DefaultUserName").DefaultUserName
Write-Host $DefaultUserName

I am using the following c# lines to execute the powershell script from the windows service:

var process = new Process();
process.StartInfo.UseShellExecute = false;
process.StartInfo.FileName = @"C:\Windows\SysWOW64\WindowsPowerShell\v1.0\powershell.exe";
process.StartInfo.Arguments = "\"&'"   cacheFile   "'\"";
process.StartInfo.Verb = "runas";
process.Start();

CodePudding user response：

You need to be careful of bitness. On 64-bit Windows, 32-bit applications run using the 'Windows on Windows' subsystem, which by default uses different filesystem paths and registry paths. You are executing powershell from the SysWOW64 folder, which means you are executing the 32-bit version, which will use the 32-bit registry hive.

If you open up regedit, the 32-bit hive for your registry key is: Computer\HKEY_LOCAL_MACHINE\SOFTWARE\WOW6432Node\Microsoft\Windows NT\CurrentVersion\Winlogon. I suspect you are getting/setting this value.

Please refer to How to access a 64Bit Registry key using 32Bit Powershell without Redirection to WOW6432Node for strategies you can take, including using the Sysnative rather than SysWOW64 version of powershell.

If you need to support 32-bit and 64-bit operating systems, you will need to make sure you are using the appropriate technique.

CodePudding user response：

This answer has beautiful explanation of Windows built in accounts : The difference between the 'Local System' account and the 'Network Service' account?

A limited service account that is very similar to Network Service and meant to run standard least-privileged services. However, unlike Network Service it accesses the network as an Anonymous user

Completely trusted account, more so than the administrator account. There is nothing on a single box that this account cannot do, and it has the right to access the network as the machine (this requires Active Directory and granting the machine account permissions to something)

Also can you try running the service as SYSTEM?