Use Command Prompt to access another computer
In today’s lesson in our Geek School series covering SysInternals, we’re going to show you how to use the PsTools set of utilities to perform all sorts of administration tasks both locally, and on remote computers as well.
If you’ve ever wanted to connect to another computer and run a command, quickly get information about processes running and optionally kill them, or even stop a service on another PC, you can use the PsTools utilities to do all of these things and even more.
Obviously you can use Remote Desktop or a similar service to connect to any Windows computer and actually see the desktop and do anything that you would do locally, but the PsTools utilities allow you to do many tasks from the command line — or better yet, from a script that you can re-use later.
These are the type of utilities that work best in a corporate environment, and mastering these tools will definitely make you much better at your system administration job, save you time, and let you do things in a much smarter way. Doing things smarter and faster is a critical skill for being a great sysadmin.
There are twelve tools in the PsTools set, and while some of them are extremely useful, others have been superseded with tools built into more recent versions of Windows, and there are a few others which aren’t useful for most people. We’ll go through all of them so you understand how they work and why you might want to use each one.
- PsExec – executes processes on a remote computer
- PsFile – shows files that are opened on the remote computer through the network
- PsGetSid – displays the security identifier for a computer or user
- PsInfo – lists information about a system
- PsKill – kills processes by name or ID
- PsList – list information about processes on the command line
- PsLoggedOn – list accounts that are logged on either on the machine or connecting remotely
- PsLogList – pull the event log on the command line
- PsPasswd – change the password for users
- PsPing – a fairly simple ping utility with some additional features
- PsService – list and make changes to Windows services
- PsShutdown – shut down, log off, or suspend a computer
- PsSuspend – suspend and resume processes (rather than killing them)
It’s worth noting that you can use a tool like PsExec to execute all sorts of command-line utilities on remote computers… including really useful ones like the Autoruns command line tool and many more. The possibilities are endless once you’ve embraced the power of PsTools.
All of these tools can be used on local computers, but they are mostly useful for connecting to remote computers and performing commands on them.
Connecting to Remote Computers ( Syntax for All Utilities)
All of the utilites can be run on either the local or remote computer, so they all have the same first argument for computer name if needed. Note that you could use the IP address if you wanted instead. If you omit this argument, the command will operate on your local computer.
You can also list multiple computers like psinfo \\computer1, computer2, computer3, or you could put all of the names into a file and reference that like psinfo @computerlist.txt. The final syntax is psinfo \\* which operates on all computers in the domain, which probably isn’t something you’ll use every day.
If you need to connect with alternate credentials because your local computer’s account has a different username and password than the other computer, you can use the -u and -p options, though we’d note that you might not want to use -p on the command line with a password in the command for security reasons.
psinfo \\computername -u “user” -p “Password”
The “user” part of the command would change to “DOMAIN\user” if you are in a domain environment and need to change from the currently running user.
Note: you will generally need to connect to the remote computers with an administrator account.
Configuring Remote Administration Access
If you are in a domain environment, which most people that need to use PsTools will be, you can ignore this section entirely as everything should work just fine. For anybody running Windows 7, 8, or Vista in a home environment or using a couple of computers in an office without a domain, you will need to tweak User Account Control on the remote computer to allow PsTools to properly run.
When a user who is a member of the local administrators group on the target remote computer establishes a remote administrative connection by using the net use * \\remotecomputer\Share$ command, for example, they will not connect as a full administrator. The user has no elevation potential on the remote computer, and the user cannot perform administrative tasks.
To explain it in a different way, when you try to connect to another computer and run something that requires administrator access, there is no way to trigger the UAC prompt and accept it from your computer, so it won’t connect as administrator.
And this isn’t a bad thing. You shouldn’t change this setting without fully understanding that you will be allowing an opening for malware to spread from one computer to another — assuming that malware has your local username and password, and that password is the same as the other computer, and the malware is that tricky, which most isn’t. But it still isn’t something to be taken lightly.
And again, if you are in a domain environment, this problem doesn’t exist and doesn’t need to be changed. And if you are just testing with a bunch of virtual machines, you don’t have much to worry about.
To tweak UAC to enable PsTools to run you’ll want to open up the Registry Editor and navigate to the following key:
Once you are there, create a new 32-bit DWORD on the right-hand side, give it the name LocalAccountTokenFilterPolicy and the value of 1. You don’t have to restart the computer to make the setting take effect.
Note: just to clarify, this setting needs to happen on the remote computer that you are connecting to.
PsExec is probably the most powerful tool in the kit, as you can execute any command in your local command prompt just like executing it on the remote computer. That includes anything that can be run on the command line — you can change registry values, run scripts and utilities, or connect from that PC to another one. The output of the commands will be shown on your local PC, rather than on the remote one.