In Windows, there are a lot of different groups for services. the earliest one is System reserved.
So can user mode services use any of them? or is there a limit for user mode applications?
For example i wrote a test app that writes/reads files, obviously this shouldn't work in the first group (System reserved) since file system drivers are not yet loaded (?), but it does work, so i thought maybe Windows is not executing it in that group since its a user mode app?
I'm developing a Windows application that must execute other GUI programs with privileges (executed as administrator).
Scope
My application is a "daemon", a long-running process that it will be launched with no user action;
My application must be executed as administrator (privileges elevation);
Processes executed by my application must be executed as administrator and must display on the screen.
Approach
Firstly, I developed my application as Windows service. I thought that it was the best way to run programs with privileges but services can't run programs that use the GUI session.
This restriction has been introduced by Microsoft with Windows Vista. An article from Microsoft - Impact of Session 0 Isolation on Services and Drivers in Windows - explains these changes. I tried to change the user who runs my service but this isolation appears to apply for all services.
Purpose
So my question is "What's the best way to run a program that it will launch another program with elevation of privileges (executed as administrator) with no action from user ?"
Currently, the only once idea to solve my problem is to register my application into Task Scheduler but I think that it probably exists a best way.
Windows Services have not been designed to interact in current session (user session). Services are running into Session 0 since the deployment of Windows Vista.
Explanations about this changes can be found in "Impact of Session 0 Isolation on Services and Drivers in Windows".
I have found another Microsoft post "Launching an interactive process from Windows Service in Windows Vista and later" but we can read at the beginning:
The first thing you should do about it is that, don't do it. There are many limitations, bad implications and restrictions involved into it.
Windows Services are definitely a wrong solution for this use case. The unique solution that I can found is the Task Scheduler.
Is there a way to find out what privileges my application needs in order to run in a Windows 7 environment?
I have a Delphi application that is using BDE and ODBC for database connectivity. This application works on most computers with Windows 7 running on a normal user account. However on some computers it only works on accounts with administrative privileges and is not working correctly on normal user accounts. I suspect it's a permission problem. The computers also are running in Active Directory.
I tried to find some informations using Process Monitor from SysInternals, however the output for me is too advanced. The process monitor log for two runs of my app (1. successful with administrative rights, 2. unsuccessfull on normal rights) had over 22k lines and i could not find the answer (needle) in the process monitor log (haystack).
What could i do to determine the privileges that my app needs in windows 7?
Use the Standard User Analyzer from the Microsoft Application Compatibility Toolkit.
The Standard User Analyzer (SUA) tool and the Standard User Analyzer
Wizard (SUA Wizard) both enable you to test your applications and to
monitor API calls in order to detect potential compatibility issues
due to the User Account Control (UAC) feature in the Windows® 7
operating system.
UAC, formerly known as Limited User Account (LUA), requires that all
users (including members of the Administrator group) run as Standard
Users, until the application is deliberately elevated, by using the
security prompt dialog box. However, not all applications can run
properly with the Standard User role, due to the application requiring
access and privileges for locations that are unavailable to a Standard
User.
Aaron Margosis has a tool called LUA Buglight that is designed to help track down issues related to privileges.
You can download the latest version from this blog post:
LUA Buglight 2.1.1 with support for Win7/2008R2 SP1
It is similar in concept to the MS Application Verifier. However, in practice I found LUA Buglight much easier to use and understand. Same with ProcessMonitor. It will monitor your process in a similar way but only report actions that failed as a normal user but succeeded as a admin user.
There is no documentation but it is simple to use. From the main GUI window select your Exe and let the BugLight program launch it. You need to be running in an Admin account with UAC enabled. Run your program though the steps that fail when you are not an admin. When you are done click on the Stop Logging button to see a report that lists what calls would have failed without admin rights.
Update: Since development machine has moved to Vista, i now automatically test as a standard user. And with XP being phased out, this question isn't so relavent anymore.
Since the Windows 2000 logo requirements, Microsoft has been requiring that applications run as standard user. Like everyone else i always ran my desktop as an administrative user. And like every developer: i log in, develop, run, and test as an administrative user.
Now with a new push to finally support standard users, i've been testing my applications by running them as a normal user - either through RunAs, or having my application relaunch itself with normal rights using [SaferCreateLevel][1]/[SaferComputeTokenFromLevel][2] if it detects it is running as an administrator. i quickly see how specacularly some of my apps fail under Windows XP as a standard user (due to my own stupidity). i also see how the same applications work fine under Vista (thanks to it's numerous shims to fix my bugs for me).
Aside: It's ironic that applications are more likely to run on Vista as a standard user than on XP.
The question is do you test your applications for standard user compatiblity? Do you develop as a standard user on XP? Do you ignore standard user access and hope for the best?
i tried, as a bonus, to have my app relaunch itself as a limited user (rather than normal user). It doesn't even come up - Windows says it failed to initialize. So there an area of future research on my part: making the app even support limited user.
i specifically referred to standard users on XP rather than Vista to enforce the truth that Vista is no different from XP as far as compatibility is concerned. And anyone who says their app fails on Vista must realize it also fails on XP.
I'm going to point you to Crispin Cowan's "Best Practices for Developing for Windows Standard User" talk. It's well worth watching.
If you want to sell your application to businesses then yes, you must test your application running as a standard user. If your application can't run without administrative privelleges, that's going to doom any sale in to a business.
Even in the home market, plenty of people can and do use limited users to go about their daily activities; I know I do.
Even administrative applications that do legimately need administrative privelleges should behave sensibly when running as a limited user. They should popup up a dialog informing the user that administrative rights are required to complete whatever task it was that they were attempting.
The best way to build software that respects these limitations is to develop your software under a user that has limited privileges. That way, every time you develop a feature you're implicitly testing whether it will work in a limited environment.
None of this is hard, it just take a degree of discipline - just like all quality assurance procedures do. People have been developing as non-root users on *nix for decades. Windows development is behind the curve in this respect.
Crispin, in his PDC talk, made a very good point, one that i had never considered before.
Google Chrome installs as a standard user: it installs in the per-user folder, without needing a UAC or OTS prompt, and everything is user friendly because the install is so easy. Unfortunatly, it is installed in a per-user folder, where the user can modify it.
Put it another way: malware can modify the Chrome exe.
Chrome would now become the biggest target for any mal-ware. And if some malware does modify it, Chrome is now sending your usernames, passwords, and credit card info back to home base, because that's what the new Chrome exe does.
That is why you sometimes want applications installed to protected locations.
Edit: The entire Microsoft "Click Once" deployment inititave suffers the danger.
I run on XP as a limited user almost all of the time and as the default. (On Vista, I use an adminstrative account and rely on UAC.)
I develop as a limited user. There's very little in Java and Visual Studio development that requires any more privilege than that.
If I need to run something under the limited account but with administrative privileges, I use a MakeMeAdmin (renamed and tuned as ConsoleMeAdmin) .bat script that creates an administrative console session.
If I really need to be an administrator in order to do installs and do first-time-runs so my security software can condition itself to allow network access to the new code (or not), etc., I will elevate my Limited User Account to Administrator long enough to get all of that done, then restart the account as Limited User again. Other than for Windows Updates, I do all of my downloads as a limited user and then install off-line after elevation to Administrator.
Because I only have a small workgroup LAN with no Active Directory, the only useful account types are Administrator and Limited User on XP. (I tried power user when I first began using XP but found that I could do without it and I prefer what that teaches me about not depending on special privileges in code I build.)
[PS: I also have Data Execution Protection (supported in hardware) active by default on my XP system, and you'd be surprised what that turns up.]
In the business environment most users are standard windows domain users.
To ignore standard user compliance tests is a really bad move.
And you will get each domain administrator that has to install your application very angry and they will go to your competition.
IMHO developing in an administrator account is not only unnecessary, but also highly dangerous! Suppose you check something on the internet while developing (stackoverflow comes to mind) and you catch some malware - history shows that this is far easier than you might have thought, e.g. through banners. As an administrator this malware will infect your computer and you might never get rid of it. It can even be a danger to all your development work (think of industrial espionage)!
If you have to run/test anything as an administrator, use either runas or even better virtual machines - that way you can use separate systems with defined behaviour (lots of problems with Windows software come from libraries that are of course available on the developer's PC, but hardly anywhere else!). In times of Microsoft Virtual PC and VMWare Server (both free) there isn't even an excuse due to high prices for virtualization software.
I've developed some Windows apps some years ago and besides their installers NOTHING ever required administrative rights. The run-time settings always belong to the user, not to the machine.
And yes, I run Windows XP as normal user at home too, as do my family members (parents etc.). Sometimes a crappy piece of software needs write access to their installation folder, but 95% of all installed apps run fine out-of-the-box by today.
Yes, we test that.
Probably the simplest, but most abused, rule is that you shouldn't do anything that requires write access to your program's install folder. Instead, there's a special folder called Application Data for that kind of thing.
Yes, and I took the general advice that its much easier to get your application to run on Vista if it runs ok on XP as limited user. To achieve that, and know if there were any problems running as limited user, I used LUABuglight.
I generally don't develop as limited user but only log on as limited user for testing.
The number of programs that require Admin rights and write to their own Program Files folder is amazing. To be honest, I've found very few programs that run correctly as limited user, from any software company, big or small.
Anyone else find it funny that Windows developers think its normal to run as Admin (apparently), but Linux developers pretty much never run as root?
As an old-time BOFH I will rain fire and ugly words over anyone asking for elevated rights for their client-side applications to run properly. It's just out of the question, always was ever since around 2001-2002 when we switched from Win9x to XP (sic).
As a newly born developer in a place where everyone on XP is a local admin by a forced group policy and changing it seems to take time and noone is especially inclined to start either - I've installed the RunAsAdmin shim that lowers me down to a normal user for most tasks including developing - much like in Vista. Recommended if you're stuck as a local admin on XP ^^
This is a Windows 2003 (or later) machine that gets switched on every morning, but no one logs on until some hours later.
I want to use the time in between to run a backup script c:\script\backup.cmd
How can I start this unattended after the machine has come up?
I tried 2 registry keys, but this resulted in the script being run after a user logs on (which is too late):
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\RunServices
In the end I used Windows TaskScheduler, who has such an option, but I was wondering if there is another possibility?
Short answer: GPEDIT.MSC (Start, Run, GPEdit.msc)
Windows 2000 and above [1] offer a computer Startup Scripts collection in the policy editor:
Computer Settings -> Windows Settings -> Scripts (Startup/Shutdown)
There's an equivalent logon script area (i.e. after computer startup, when a user logs on) in the User configuration bit.
Longer:
GPEDIT.MSC is the Group Policy editing console, and runs against the local computer's Local Group Policy store when it's used directly, so it's useful for setting local-only parameters. When using Active Directory, a similar interface is used to edit AD Forest-hosted group policy objects (GPOs), so the same settings are available across a bunch of machines.
The computer startup scripts run in the computer context, i.e. as LocalSystem, as you noted, so they often can't access network drives which require a certain user or group membership to work. When domain-member computers access network resources, they generally (with exceptions) authenticate using their MACHINENAME$ account - which lets you set Share/NTFS permissions to allow a computer to access those resources.
A startup script is a quick and easy way of getting a process running when the machine boots.
The computer startup process will be affected by the time it takes to run the program, though, so you might want to ensure you call it with the START command from a batch file, or specifying not to wait for the executable to complete in whatever script language you use. (the key point there is: run the script asynchronously unless it's critical, or doesn't need to be run asynchronously cos it will always take no time at all. Long boots = unhappy users).
Using a Win32 Service is an alternative option - you can use the SRVANY utility from the Resource Kit to "service-ify" pretty much any executable. VS.Net 2002 and later also let you build a managed service directly.
And Task Scheduler gets much more capable as of Vista/2008, able to run scripts at startup, on idle, and/or when Event Logs are generated or certain other conditions are met: it's pretty cool! Scheduled Tasks has the possible advantage of being able to specify the user account under which the task runs, if that's important to you.
Caveat Scriptor:
http://support.microsoft.com/kb/256320
Run Startup Scripts Asynchronously:
http://msdn.microsoft.com/en-us/library/ms811602.aspx
Vista Task Scheduler (what's new):
http://technet.microsoft.com/en-us/appcompat/aa906020.aspx
[1] Windows XP, 2003, Vista/2008, Windows 7/2008R2, Windows 8/2012, Windows 8.1/2012R2, Windows 10/Windows Server 2016. Everything. But NT4 didn't!
You have already outlined a good solution:
Setup a scheduled task to run at Start Up and allow the job to run when the user isn't logged on.
You can run a script at system startup using group policy gpedit.msc
The way you aleady do this seems fine to me; however if you want an alternative approach then services get started when the machine boots so you could write a service that detects if it's a new day (to allow for reboots) and if it is then run your backup.
If I was doing this as a service I'd use TCL because I know it and like it and it has an extension twapi that allows you to run a script as a service. Other scripting languages may well have similar facilities.
There is, if you're using Active Directory. If you can isolate the computer to its own OU or use WMI filtering, you could assign a GPO which has a startup script for the computer. This would ensure that even if someone went in via safe mode and disabled the Task Scheduler, upon startup and connection to the domain, the script would run.