Set-TokenPrivilege.ps1

param(    ## The privilege to adjust. This set is taken from
    ## http://msdn.microsoft.com/en-us/library/bb530716(VS.85).aspx

    [ValidateSet(
        "SeAssignPrimaryTokenPrivilege", "SeAuditPrivilege", "SeBackupPrivilege",
        "SeChangeNotifyPrivilege", "SeCreateGlobalPrivilege", "SeCreatePagefilePrivilege",
        "SeCreatePermanentPrivilege", "SeCreateSymbolicLinkPrivilege", "SeCreateTokenPrivilege",
        "SeDebugPrivilege", "SeEnableDelegationPrivilege", "SeImpersonatePrivilege", "SeIncreaseBasePriorityPrivilege",
        "SeIncreaseQuotaPrivilege", "SeIncreaseWorkingSetPrivilege", "SeLoadDriverPrivilege",
        "SeLockMemoryPrivilege", "SeMachineAccountPrivilege", "SeManageVolumePrivilege",
        "SeProfileSingleProcessPrivilege", "SeRelabelPrivilege", "SeRemoteShutdownPrivilege",
        "SeRestorePrivilege", "SeSecurityPrivilege", "SeShutdownPrivilege", "SeSyncAgentPrivilege",
        "SeSystemEnvironmentPrivilege", "SeSystemProfilePrivilege", "SeSystemtimePrivilege",
        "SeTakeOwnershipPrivilege", "SeTcbPrivilege", "SeTimeZonePrivilege", "SeTrustedCredManAccessPrivilege",
        "SeUndockPrivilege", "SeUnsolicitedInputPrivilege")]
    $Privilege,

    ## The process on which to adjust the privilege. Defaults to the current process.
    $ProcessId = $pid,

    ## Switch to disable the privilege, rather than enable it.
    [Switch] $Disable
)

## Taken from P/Invoke.NET with minor adjustments.
$definition = @'
using System;

using System.Runtime.InteropServices;
public class AdjPriv
{
    [DllImport("advapi32.dll", ExactSpelling = true, SetLastError = true)]
    internal static extern bool AdjustTokenPrivileges(IntPtr htok, bool disall,
        ref TokPriv1Luid newst, int len, IntPtr prev, IntPtr relen);

    [DllImport("advapi32.dll", ExactSpelling = true, SetLastError = true)]
    internal static extern bool OpenProcessToken(IntPtr h, int acc, ref IntPtr phtok);

    [DllImport("advapi32.dll", SetLastError = true)]
    internal static extern bool LookupPrivilegeValue(string host, string name, ref long pluid);

    [StructLayout(LayoutKind.Sequential, Pack = 1)]
    internal struct TokPriv1Luid
    {
        public int Count;
        public long Luid;
        public int Attr;
    }

    internal const int SE_PRIVILEGE_ENABLED = 0x00000002;
    internal const int SE_PRIVILEGE_DISABLED = 0x00000000;
    internal const int TOKEN_QUERY = 0x00000008;
    internal const int TOKEN_ADJUST_PRIVILEGES = 0x00000020;

    public static bool EnablePrivilege(long processHandle, string privilege, bool disable)
    {
        bool retVal;
        TokPriv1Luid tp;
        IntPtr hproc = new IntPtr(processHandle);
        IntPtr htok = IntPtr.Zero;
        retVal = OpenProcessToken(hproc, TOKEN_ADJUST_PRIVILEGES | TOKEN_QUERY, ref htok);
        tp.Count = 1;
        tp.Luid = 0;

        if(disable)
        {
            tp.Attr = SE_PRIVILEGE_DISABLED;
        }
        else
        {
            tp.Attr = SE_PRIVILEGE_ENABLED;
        }

        retVal = LookupPrivilegeValue(null, privilege, ref tp.Luid);
        retVal = AdjustTokenPrivileges(htok, false, ref tp, 0, IntPtr.Zero, IntPtr.Zero);
        return retVal;
    }
}
'@

$processHandle = (Get-Process -id $ProcessId).Handle
$type = Add-Type $definition -PassThru
$type[0]::EnablePrivilege($processHandle, $Privilege, $Disable)