[windows-services] How do you run CMD.exe under the Local System Account?

I'm currently running Vista and I would like to manually complete the same operations as my Windows Service. Since the Windows Service is running under the Local System Account, I would like to emulate this same behavior. Basically, I would like to run CMD.EXE under the Local System Account.

I found information online which suggests lauching the CMD.exe using the DOS Task Scheduler AT command, but I received a Vista warning that "due to security enhancements, this task will run at the time excepted but not interactively." Here's a sample command:

AT 12:00 /interactive cmd.exe

Another solution suggested creating a secondary Windows Service via the Service Control (sc.exe) which merely launches CMD.exe.

C:\sc create RunCMDAsLSA binpath= "cmd" type=own type=interact
C:\sc start RunCMDAsLSA

In this case the service fails to start and results it the following error message:

FAILED 1053: The service did not respond to the start or control request in a timely fashion.

The third suggestion was to launch CMD.exe via a Scheduled Task. Though you may run scheduled tasks under various accounts, I don't believe the Local System Account is one of them.

I've tried using the Runas as well, but think I'm running into the same restriction as found when running a scheduled task.

Thus far, each of my attempts have ended in failure. Any suggestions?

I would recommend you work out the minimum permission set that your service really needs and use that, rather than the far too privileged Local System context. For example, Local Service.

Interactive services no longer work - or at least, no longer show UI - on Windows Vista and Windows Server 2008 due to session 0 isolation.

I use the RunAsTi utility to run as TrustedInstaller (high privilege). The utility can be used even in recovery mode of Windows (the mode you enter by doing Shift+Restart), the psexec utility doesn't work there. But you need to add your C:\Windows and C:\Windows\System32 (not X:\Windows and X:\Windows\System32) paths to the PATH environment variable, otherwise RunAsTi won't work in recovery mode, it will just print: AdjustTokenPrivileges for SeImpersonateName: Not all privileges or groups referenced are assigned to the caller.

Using task scheduler, schedule a run of CMDKEY running under SYSTEM with the appropriate arguments of /add: /user: and /pass:

No need to install anything.

I would recommend you work out the minimum permission set that your service really needs and use that, rather than the far too privileged Local System context. For example, Local Service.

Interactive services no longer work - or at least, no longer show UI - on Windows Vista and Windows Server 2008 due to session 0 isolation.

an alternative to this is Process hacker if you go into run as... (Interactive doesnt work for people with the security enhancments but that wont matter) and when box opens put Service into the box type and put SYSTEM into user box and put C:\Users\Windows\system32\cmd.exe leave the rest click ok and boch you have got a window with cmd on it and run as system now do the other steps for yourself because im suggesting you know them

I use the RunAsTi utility to run as TrustedInstaller (high privilege). The utility can be used even in recovery mode of Windows (the mode you enter by doing Shift+Restart), the psexec utility doesn't work there. But you need to add your C:\Windows and C:\Windows\System32 (not X:\Windows and X:\Windows\System32) paths to the PATH environment variable, otherwise RunAsTi won't work in recovery mode, it will just print: AdjustTokenPrivileges for SeImpersonateName: Not all privileges or groups referenced are assigned to the caller.

1. Download psexec.exe from Sysinternals.
2. Place it in your C:\ drive.
3. Logon as a standard or admin user and use the following command: cd \. This places you in the root directory of your drive, where psexec is located.
4. Use the following command: psexec -i -s cmd.exe where -i is for interactive and -s is for system account.
5. When the command completes, a cmd shell will be launched. Type whoami; it will say 'system"
6. Open taskmanager. Kill explorer.exe.
7. From an elevated command shell type start explorer.exe.
8. When explorer is launched notice the name "system" in start menu bar. Now you can delete some files in system32 directory which as admin you can't delete or as admin you would have to try hard to change permissions to delete those files.

Users who try to rename or deleate System files in any protected directory of windows should know that all windows files are protected by DACLS while renaming a file you have to change the owner and replace TrustedInstaller which owns the file and make any user like a user who belongs to administrator group as owner of file then try to rename it after changing the permission, it will work and while you are running windows explorer with kernel privilages you are somewhat limited in terms of Network access for security reasons and it is still a research topic for me to get access back

Using Secure Desktop to run cmd.exe as system

We can get kernel access through CMD in Windows XP/Vista/7/8.1 easily by attaching a debugger:

REG ADD "HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options\osk.exe" /v Debugger /t REG_SZ /d "C:\windows\system32\cmd.exe"

1. Run CMD as Administrator

2. Then use this command in Elevated:

    CMD REG ADD "HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options\osk.exe" /v Debugger /t REG_SZ /d "C:\windows\system32\cmd.exe"
   

3. Then run osk (onscreenkeyboard). It still does not run with system Integrity level if you check through process explorer, but if you can use OSK in service session, it will run as NT Authority\SYSTEM

so I had the idea you have to run it on Secure Desktop.

Start any file as Administrator. When UAC prompts appear, just press Win+U and start OSK and it will start CMD instead. Then in the elevated prompt, type whoami and you will get NT Authority\System. After that, you can start Explorer from the system command shell and use the System profile, but you are somewhat limited what you can do on the network through SYSTEM privileges for security reasons. I will add more explanation later as I discovered it a year ago.

A Brief Explanation of how this happens

Running Cmd.exe Under Local System Account Without Using PsExec. This method runs Debugger Trap technique that was discovered earlier, well this technique has its own benefits it can be used to trap some crafty/malicious worm or malware in the debugger and run some other exe instead to stop the spread or damage temporary. here this registry key traps onscreen keyboard in windows native debugger and runs cmd.exe instead but cmd will still run with Logged on users privileges, however if we run cmd in session0 we can get system shell. so we add here another idea we span the cmd on secure desktop remember secure desktop runs in session 0 under system account and we get system shell. So whenever you run anything as elevated, you have to answer the UAC prompt and UAC prompts on dark, non interactive desktop and once you see it you have to press Win+U and then select OSK you will get CMD.exe running under Local system privileges. There are even more ways to get local system access with CMD

if you can write a batch file that does not need to be interactive, try running that batch file as a service, to do what needs to be done.

(Comment)

I can't comment yet, so posting here... I just tried the above OSK.EXE debug trick but regedit instantly closes when I save the filled "C:\windows\system32\cmd.exe" into the already created Debugger key so Microsoft is actively working to block native ways to do this. It is really weird because other things do not trigger this.

Using task scheduler does create a SYSTEM CMD but it is in the system environment and not displayed within a human user profile so this is also now defunct (though it is logical).

Currently on Microsoft Windows [Version 10.0.20201.1000]

So, at this point it has to be third party software that mediates this and further tricks are being more actively sealed by Microsoft these days.

Found an answer here which seems to solve the problem by adding /k start to the binPath parameter. So that would give you:

sc create testsvc binpath= "cmd /K start" type= own type= interact

However, Ben said that didn't work for him and when I tried it on Windows Server 2008 it did create the cmd.exe process under local system, but it wasn't interactive (I couldn't see the window).

I don't think there is an easy way to do what you ask, but I'm wondering why you're doing it at all? Are you just trying to see what is happening when you run your service? Seems like you could just use logging to determine what is happening instead of having to run the exe as local system...

I would recommend you work out the minimum permission set that your service really needs and use that, rather than the far too privileged Local System context. For example, Local Service.

Interactive services no longer work - or at least, no longer show UI - on Windows Vista and Windows Server 2008 due to session 0 isolation.

if you can write a batch file that does not need to be interactive, try running that batch file as a service, to do what needs to be done.

1. Download psexec.exe from Sysinternals.
2. Place it in your C:\ drive.
3. Logon as a standard or admin user and use the following command: cd \. This places you in the root directory of your drive, where psexec is located.
4. Use the following command: psexec -i -s cmd.exe where -i is for interactive and -s is for system account.
5. When the command completes, a cmd shell will be launched. Type whoami; it will say 'system"
6. Open taskmanager. Kill explorer.exe.
7. From an elevated command shell type start explorer.exe.
8. When explorer is launched notice the name "system" in start menu bar. Now you can delete some files in system32 directory which as admin you can't delete or as admin you would have to try hard to change permissions to delete those files.

Users who try to rename or deleate System files in any protected directory of windows should know that all windows files are protected by DACLS while renaming a file you have to change the owner and replace TrustedInstaller which owns the file and make any user like a user who belongs to administrator group as owner of file then try to rename it after changing the permission, it will work and while you are running windows explorer with kernel privilages you are somewhat limited in terms of Network access for security reasons and it is still a research topic for me to get access back

Using Secure Desktop to run cmd.exe as system

We can get kernel access through CMD in Windows XP/Vista/7/8.1 easily by attaching a debugger:

REG ADD "HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options\osk.exe" /v Debugger /t REG_SZ /d "C:\windows\system32\cmd.exe"

1. Run CMD as Administrator

2. Then use this command in Elevated:

    CMD REG ADD "HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options\osk.exe" /v Debugger /t REG_SZ /d "C:\windows\system32\cmd.exe"
   

3. Then run osk (onscreenkeyboard). It still does not run with system Integrity level if you check through process explorer, but if you can use OSK in service session, it will run as NT Authority\SYSTEM

so I had the idea you have to run it on Secure Desktop.

Start any file as Administrator. When UAC prompts appear, just press Win+U and start OSK and it will start CMD instead. Then in the elevated prompt, type whoami and you will get NT Authority\System. After that, you can start Explorer from the system command shell and use the System profile, but you are somewhat limited what you can do on the network through SYSTEM privileges for security reasons. I will add more explanation later as I discovered it a year ago.

A Brief Explanation of how this happens

Running Cmd.exe Under Local System Account Without Using PsExec. This method runs Debugger Trap technique that was discovered earlier, well this technique has its own benefits it can be used to trap some crafty/malicious worm or malware in the debugger and run some other exe instead to stop the spread or damage temporary. here this registry key traps onscreen keyboard in windows native debugger and runs cmd.exe instead but cmd will still run with Logged on users privileges, however if we run cmd in session0 we can get system shell. so we add here another idea we span the cmd on secure desktop remember secure desktop runs in session 0 under system account and we get system shell. So whenever you run anything as elevated, you have to answer the UAC prompt and UAC prompts on dark, non interactive desktop and once you see it you have to press Win+U and then select OSK you will get CMD.exe running under Local system privileges. There are even more ways to get local system access with CMD

(Comment)

I can't comment yet, so posting here... I just tried the above OSK.EXE debug trick but regedit instantly closes when I save the filled "C:\windows\system32\cmd.exe" into the already created Debugger key so Microsoft is actively working to block native ways to do this. It is really weird because other things do not trigger this.

Using task scheduler does create a SYSTEM CMD but it is in the system environment and not displayed within a human user profile so this is also now defunct (though it is logical).

Currently on Microsoft Windows [Version 10.0.20201.1000]

So, at this point it has to be third party software that mediates this and further tricks are being more actively sealed by Microsoft these days.

Found an answer here which seems to solve the problem by adding /k start to the binPath parameter. So that would give you:

sc create testsvc binpath= "cmd /K start" type= own type= interact

However, Ben said that didn't work for him and when I tried it on Windows Server 2008 it did create the cmd.exe process under local system, but it wasn't interactive (I couldn't see the window).

I don't think there is an easy way to do what you ask, but I'm wondering why you're doing it at all? Are you just trying to see what is happening when you run your service? Seems like you could just use logging to determine what is happening instead of having to run the exe as local system...

I would recommend you work out the minimum permission set that your service really needs and use that, rather than the far too privileged Local System context. For example, Local Service.

Interactive services no longer work - or at least, no longer show UI - on Windows Vista and Windows Server 2008 due to session 0 isolation.

Found an answer here which seems to solve the problem by adding /k start to the binPath parameter. So that would give you:

sc create testsvc binpath= "cmd /K start" type= own type= interact

However, Ben said that didn't work for him and when I tried it on Windows Server 2008 it did create the cmd.exe process under local system, but it wasn't interactive (I couldn't see the window).

I don't think there is an easy way to do what you ask, but I'm wondering why you're doing it at all? Are you just trying to see what is happening when you run your service? Seems like you could just use logging to determine what is happening instead of having to run the exe as local system...

if you can write a batch file that does not need to be interactive, try running that batch file as a service, to do what needs to be done.

an alternative to this is Process hacker if you go into run as... (Interactive doesnt work for people with the security enhancments but that wont matter) and when box opens put Service into the box type and put SYSTEM into user box and put C:\Users\Windows\system32\cmd.exe leave the rest click ok and boch you have got a window with cmd on it and run as system now do the other steps for yourself because im suggesting you know them

if you can write a batch file that does not need to be interactive, try running that batch file as a service, to do what needs to be done.

There is another way. There is a program called PowerRun which allows for elevated cmd to be run. Even with TrustedInstaller rights. It allows for both console and GUI commands.

Using task scheduler, schedule a run of CMDKEY running under SYSTEM with the appropriate arguments of /add: /user: and /pass:

No need to install anything.