Batch script: how to check for admin rights

blak3r / Rushyo's solution works fine for everything except Windows 8. Running AT on Windows 8 results in:

The AT command has been deprecated. Please use schtasks.exe instead.

The request is not supported.

(see screenshot #1) and will return %errorLevel% 1.

 

Research

So, I went searching for other commands that require elevated permissions. rationallyparanoid.com had a list of a few, so I ran each command on the two opposite extremes of current Windows OSs (XP and 8) in the hopes of finding a command that would be denied access on both OSs when run with standard permissions.

Eventually, I did find one - NET SESSION. A true, clean, universal solution that doesn't involve:

• the creation of or interaction with data in secure locations
• analyzing data returned from FOR loops
• searching strings for "Administrator"
• using AT (Windows 8 incompatible) or WHOAMI (Windows XP incompatible).

Each of which have their own security, usability, and portability issues.

 

Testing

I've independently confirmed that this works on:

• Windows XP, x86
• Windows XP, x64
• Windows Vista, x86
• Windows Vista, x64
• Windows 7, x86
• Windows 7, x64
• Windows 8, x86
• Windows 8, x64

(see screenshot #2)

 

Implementation / Usage

So, to use this solution, simply do something like this:

@echo off
goto check_Permissions

:check_Permissions
    echo Administrative permissions required. Detecting permissions...

    net session >nul 2>&1
    if %errorLevel% == 0 (
        echo Success: Administrative permissions confirmed.
    ) else (
        echo Failure: Current permissions inadequate.
    )

    pause >nul

Available here, if you're lazy:https://dl.dropbox.com/u/27573003/Distribution/Binaries/check_Permissions.bat

 

Explanation

NET SESSION is a standard command used to "manage server computer connections. Used without parameters, [it] displays information about all sessions with the local computer."

So, here's the basic process of my given implementation:

1. @echo off
   • Disable displaying of commands
2. goto check_Permissions
   • Jump to the :check_Permissions code block
3. net session >nul 2>&1
   • Run command
   • Hide visual output of command by
     1. Redirecting the standard output (numeric handle 1 / STDOUT) stream to nul
     2. Redirecting the standard error output stream (numeric handle 2 / STDERR) to the same destination as numeric handle 1
4. if %errorLevel% == 0
   • If the value of the exit code (%errorLevel%) is 0 then this means that no errors have occurred and, therefore, the immediate previous command ran successfully
5. else
   • If the value of the exit code (%errorLevel%) is not 0 then this means that errors have occurred and, therefore, the immediate previous command ran unsuccessfully
6. The code between the respective parenthesis will be executed depending on which criteria is met

 

Screenshots

Windows 8 AT %errorLevel%:

 

NET SESSION on Windows XP x86 - Windows 8 x64: