How To Run Process As Different User From Windows Service

I've created a service which is already started before a user logs in. The service is running as 'Network Service' user. From time to time it has to run an update process which nee

Solution 1:

Finally I've found out how to do this. It is rather complicated and I had to merge the code from several examples (some of them in C). The below example works when executed as Network Service or System user. It doesn't matter if executed in user session or session 0.

Here is the code:

import os
import msvcrt
import win32security
import win32con
import win32pipe
import win32process
import win32api
import win32net
import win32file
import win32event
import win32profile
import win32service


GENERIC_ACCESS = win32con.GENERIC_READ | win32con.GENERIC_WRITE | win32con.GENERIC_EXECUTE | win32con.GENERIC_ALL

WINSTA_ALL = (win32con.WINSTA_ACCESSCLIPBOARD  | win32con.WINSTA_ACCESSGLOBALATOMS | \
win32con.WINSTA_CREATEDESKTOP    | win32con.WINSTA_ENUMDESKTOPS      | \
win32con.WINSTA_ENUMERATE        | win32con.WINSTA_EXITWINDOWS       | \
win32con.WINSTA_READATTRIBUTES   | win32con.WINSTA_READSCREEN        | \
win32con.WINSTA_WRITEATTRIBUTES  | win32con.DELETE                   | \
win32con.READ_CONTROL            | win32con.WRITE_DAC                | \
win32con.WRITE_OWNER)

DESKTOP_ALL = (win32con.DESKTOP_CREATEMENU      | win32con.DESKTOP_CREATEWINDOW  | \
win32con.DESKTOP_ENUMERATE       | win32con.DESKTOP_HOOKCONTROL   | \
win32con.DESKTOP_JOURNALPLAYBACK | win32con.DESKTOP_JOURNALRECORD | \
win32con.DESKTOP_READOBJECTS     | win32con.DESKTOP_SWITCHDESKTOP | \
win32con.DESKTOP_WRITEOBJECTS    | win32con.DELETE                | \
win32con.READ_CONTROL            | win32con.WRITE_DAC             | \
win32con.WRITE_OWNER)


defrunAsDomainUser(domainName, userName, password, cmdLine, maxWait):
    # maxWait = Maximum execution time in ms
    userGroupSid = win32security.LookupAccountName(domainName, userName)[0]
    # Login as domain user and create new session
    userToken = win32security.LogonUser(userName, domainName, password,
                                        win32con.LOGON32_LOGON_INTERACTIVE,
                                        win32con.LOGON32_PROVIDER_DEFAULT)
    rc = win32api.GetLastError()
    if userToken isNoneor (rc != 0):
        return -1, "", "LogonUser failed with RC=%d!" % rc
    profileDir = win32profile.GetUserProfileDirectory(userToken)
    tokenUser = win32security.GetTokenInformation(userToken, win32security.TokenUser)

    # Set access rights to window station
    hWinSta = win32service.OpenWindowStation("winsta0", False, win32con.READ_CONTROL | win32con.WRITE_DAC )
    # Get security descriptor by winsta0-handle
    secDescWinSta = win32security.GetUserObjectSecurity(hWinSta, win32security.OWNER_SECURITY_INFORMATION
                                                                 | win32security.DACL_SECURITY_INFORMATION
                                                                 | win32con.GROUP_SECURITY_INFORMATION)
    # Get DACL from security descriptor
    daclWinSta = secDescWinSta.GetSecurityDescriptorDacl()
    if daclWinSta isNone:
        # Create DACL if not exisiting
        daclWinSta = win32security.ACL()
    # Add ACEs to DACL for specific user group
    daclWinSta.AddAccessAllowedAce(win32security.ACL_REVISION_DS, GENERIC_ACCESS, userGroupSid)
    daclWinSta.AddAccessAllowedAce(win32security.ACL_REVISION_DS, WINSTA_ALL, userGroupSid)
    # Set modified DACL for winsta0
    win32security.SetSecurityInfo(hWinSta, win32security.SE_WINDOW_OBJECT, win32security.DACL_SECURITY_INFORMATION,
                                  None, None, daclWinSta, None)

    # Set access rights to desktop
    hDesktop = win32service.OpenDesktop("default", 0, False, win32con.READ_CONTROL
                                                             | win32con.WRITE_DAC
                                                             | win32con.DESKTOP_WRITEOBJECTS
                                                             | win32con.DESKTOP_READOBJECTS)
    # Get security descriptor by desktop-handle
    secDescDesktop = win32security.GetUserObjectSecurity(hDesktop, win32security.OWNER_SECURITY_INFORMATION
                                                                   | win32security.DACL_SECURITY_INFORMATION
                                                                   | win32con.GROUP_SECURITY_INFORMATION )
    # Get DACL from security descriptor
    daclDesktop = secDescDesktop.GetSecurityDescriptorDacl()
    if daclDesktop isNone:
        #create DACL if not exisiting
        daclDesktop = win32security.ACL()
    # Add ACEs to DACL for specific user group
    daclDesktop.AddAccessAllowedAce(win32security.ACL_REVISION_DS, GENERIC_ACCESS, userGroupSid)
    daclDesktop.AddAccessAllowedAce(win32security.ACL_REVISION_DS, DESKTOP_ALL, userGroupSid)
    # Set modified DACL for desktop
    win32security.SetSecurityInfo(hDesktop, win32security.SE_WINDOW_OBJECT, win32security.DACL_SECURITY_INFORMATION,
                                  None, None, daclDesktop, None)

    # Setup stdin, stdOut and stderr
    secAttrs = win32security.SECURITY_ATTRIBUTES()
    secAttrs.bInheritHandle = 1
    stdOutRd, stdOutWr = win32pipe.CreatePipe(secAttrs, 0)
    stdErrRd, stdErrWr = win32pipe.CreatePipe(secAttrs, 0)

    ppid = win32api.GetCurrentProcess()
    tmp = win32api.DuplicateHandle(ppid, stdOutRd, ppid, 0, 0, win32con.DUPLICATE_SAME_ACCESS)
    win32file.CloseHandle(stdOutRd)
    stdOutRd = tmp

    environment = win32profile.CreateEnvironmentBlock(userToken, False)

    startupInfo = win32process.STARTUPINFO()
    startupInfo.dwFlags = win32con.STARTF_USESTDHANDLES
    startupInfo.hStdOutput = stdOutWr
    startupInfo.hStdError = stdErrWr

    hPrc = win32process.CreateProcessAsUser(
                            userToken,
                            None,               # appName
                            cmdLine,            # commandLineNone,               # processAttributesNone,               # threadAttributes1,                  # bInheritHandles
                            win32process.CREATE_NEW_CONSOLE, # dwCreationFlags
                            environment,        # newEnvironment
                            profileDir,         # currentDirectory
                            startupInfo)[0]

    win32file.CloseHandle(stdErrWr)
    win32file.CloseHandle(stdOutWr)
    win32security.RevertToSelf()

    # Wait for process to complete
    stdOutBuf = os.fdopen(msvcrt.open_osfhandle(stdOutRd, 0), "rb")
    stdErrBuf = os.fdopen(msvcrt.open_osfhandle(stdErrRd, 0), "rb")
    win32event.WaitForSingleObject(hPrc, maxWait)
    stdOut = stdOutBuf.read()
    stdErr = stdErrBuf.read()
    rc = win32process.GetExitCodeProcess(hPrc)
    return rc, str(stdOut, "utf-8"), str(stdErr, "utf-8")


if __name__ == "__main__":
    cmdLine = "C:/Windows/System32/cmd.exe"
    domainName = input("Domain: ")
    userName = input("User: ")
    password = input("Password: ")
    print(runAsDomainUser(domainName, userName, password, cmdLine, 60000))