I'm making a Parental Control program in C#. What I want to do is make my program cannot be exited. How can I do this in C#? I've searched on Google, but found nothing.
You can't. The Operating System always has control, so through the OS you can always exit (force kill) an application, for example through the task manager.
A light-weight solution could be another application that checks if the app is active or not. If not, start it again. The main program checks if the check program is there and starts it if necessary.
Another solution would be to run a service under an administrative account. That would only be a feasible option if you don't need to have access to the screen of the user.
Do you really mean impossible to exit ? Or just like hide the close cross or something ?
If you mean make the program impossible to kill, even in task manager, this seems to be a bad idea. If it's impossible for a user to kill a progra, how Windows would kill it ?
If I were you I would maybe protect the program shut down with a password.
AntiVirus software also achieves that. I just don't know how they do that exactly. But you should start with running your program as a service. That makes it quite difficult already for average users.
Then find out how to avoid that the service is stopped. I think you also need to run it under the system user account.
If you need a GUI for administration, then you should write a 2nd program that communicates with your service.
Here' some info how to (try to) kill an unstoppable service:
https://superuser.com/questions/338539/how-to-stop-an-unstoppable-windows-7-service/338560
So that's the opposite of what you want to achieve. Meaning, if your service stands all of these attacks, you have succeded.
After some Internet search I found these (the results 1 to 5, and 8, in searching for "c# create service avoid stopping"):
Prevent Windows service manager from stopping a service c#
Protecting a Windows Service from untrusted users
(Stop Windows Service and avoid time out warning message)
https://social.msdn.microsoft.com/Forums/vstudio/en-US/95ab8bf4-fa18-4f37-8a92-dc0b346afb76/prevent-a-user-from-killing-a-windows-service?forum=csharpgeneral
https://msdn.microsoft.com/en-us/library/9k985bc9(v=vs.110).aspx
http://www.csharp-examples.net/restart-windows-service/
Related
This question may be some times funny for all. Created an application in c# but my problem is in implementing that, the application should not be stopped in any case with out system restart. How can i do this? I heard about circular reference what is it and how can i apply it in my windows application
if it can be done using windows service then service can also be stopped from task manager but i don't want my application to stop
you can not do this, since the application can be closed using Task Manger. So the only way is to create two processes first represent your app second to check if your app is closed run it again.
You could create a service, as suggested in one comment. This will prevent people without administrative controls from stopping it. If people do have administrative control, they will be able to stop your program quite easily.
I checked for tricks kids use to go around Net Nanny. The most common trick is to install a virtual machine and use that for accessing the network. Users who aren't administrators can't install Virtual Box or the like, so the service solution will work against these, as well.
Say I have a simple C# monitoring program that is to be installed on some company computers, so I know what the employees are doing. The program is a single .exe file that works in the system tray. How do I prevent employees from closing this program? Is there a way to be notified when a program is closed?
If you don't want users to close your program, run it under a different account. Normal users can't kill processes they don't own, ie that run using different accounts. Of course, this means that you can't run your program as a simple application that displays a taskbar notification. You will have to convert it to a service.
In fact, a service makes a lot more sense than a user application in this scenario. If you want to display feedback or options to the user you can still create an app that creates a taskbar icon and communicates with your service
Set it up as a service and in the options for the service on first, second, and third failure - make it reboot the computer. Have the service login-as an service user with a strong password and prevent the users from running as Administrators. This should solve your problem and probably create a bit of annoyance at the same time.
The short answer: No.
The long answer: Yes...write a rootkit which will either guard or hide your process. Otherwise the users will be able to kill the process f.e. via the Task-Manager or any other means. Same goes for any helper processes which would monitor your application.
Would anyone be able to point me to docs/api that allow me to put a custom
button or link on windows lock screen ?
I want to be able to launch a custom program from there.
Thanks.
Ralph
What do you mean on "lock screen" ?
You can just run:
rundll32 USER32.DLL,LockWorkStation
This will lock the current user, but doesn't log off.
You can run it in "cmd" or "Run (Start Menu)"
OR... if using C, VB, Delphi, others... you can just call function "LockWorkStation" at USER32.DLL, and remember it's case sensitive.
It is highly unlikely that Microsoft would readily allow you to do something like that because it would be a security loophole of note. The point is that if no one is currently authorised to use the machine, it shouldn't be possible to run programs. Suddenly despite your best and honest intentions - your program becomes a potential backdoor to hack into machines.
The only kind of custom "application" MS might allow from the login screen would be alternate authentication mechanisms (e.g. fingerprint reader).
These would probably be implemented at the driver level, and have to interact with a very specific API. Even then, I doubt such a driver would be allowed to run an arbitrary application.
You may want to rather consider having your application run on a schedule or as a service without user interaction.
Okay I've spent the afternoon researching and haven't had much luck finding the answer to this. I am trying to prevent an application from launching via some sort of dll or background application. It is to be used in monitoring application usage and licenses at my institution. I have found leads here regarding WqlEventQuery and also FileSystemWatcher. Neither of these solutions appear to work for me because:
With WqlEventQuery I was only able to handle an event after the process was created. Using notepad as a test, notepad was visible and accessible to me before my logic closed it. I attempted to Suspend/Resume the thread (I know this is unsafe but I was testing/playing) but this just hung the window until my logic finished.
With FileSystemWatcher I was not able to get any events from launching a .exe, only creating, renaming and deleting files.
The goal here is to not let the application launch at all unless my logic allows it to launch. Is this possible? The next best solution I came up with was forcing some type of modal dialog which does not allow the user to interact with anything, once the dialog is closed the application is killed. My concern here is killing the application nicely and handling applications with high overhead when they load such as Photoshop or something. This would also interfere with a feature I was hoping to have where the user could enter a queue until a license is available. Is this my best route? Any other suggestions?
Thanks
edit: To clarify this is not a virus or anything malicious. It's not about preventing access to a blacklist or allowing access through a whitelist. The idea is to check a database on a case by case basis for certain applications and see if there is a license available for use. If there is, let the app launch, if not display a dialog letting the user know. We also will use this for monitoring and keeping track if we have enough licenses to meet demand, etc. An example of one of these apps is SPSS which have very expensive licenses but a very limited pool of people using it.
Could you use
System.Diagnostics.Process.GetProcessesByName
in a loop to look for the process?
It might work if you don't use too aggressive a polling rate.
You are indeed close, take a look at the WMI Management Events. http://msdn.microsoft.com/en-us/library/ms186151%28VS.80%29.aspx
Sample code from Microsoft: http://msdn.microsoft.com/en-us/library/ms257355(VS.80).aspx
Subscribing to the appropriate event will provide your application with the appropriate information to perform what you described.
Not sure if this is a GOOD solution but you could do something like pass a key into main so that if the key is not present or valid the application shuts down. Then when you open the application in your code, just pass the key in. Someone would then have to know the key in order to start the application.
This is assuming you have access to the application in question's source code, which upon reading your question again, I'm not so sure of.
I assume you don't have source for the application you want to prevent from loading...
Have you considered using a system policy? That would be the best-supported way to prevent a user from launching a program.
You could have a service running that force-kills any app that isn't "whitelisted", but I can't say how well that would work.
I wonder if you are taking the wrong approach. Back in the day there was a Mac app that would prevent access to the desktop and had buttons to launch a set list of applications.
IDEA
What if you had a wrapper for the approved apps then only allow your wrapper to run on the computer?
I would expect there is some way of hooking an application launch, but can't help directly on that front.
You may be able to improve your current approach by detecting the application's window opening and hiding it (move it offscreen) so that the user can't attempt to interact with it while you are trying to shut it down.
However, another approach that may be possible (depending on your circumstances) would be to write an application launcher. This simply is a replacement for the shortcut to the application that checks your licencing conditions, and then does a Process.Start to launch the real .exe at that point. This would work well for any application. (I used a system like this for starting up applications with specialised environment settings and it works beautifully)
You could combine this with your current approach as a fall-back for "clever" users who manage to circumvent your launcher.
If my understanding is right you want to create an application what will prevent the computer user to start any other process except ones for a white-list.
If this is the case, monitor the process list of processes (in a while loop) using System.Diagnostics.Process (the GetProcesses method gives the list of all running ones)
Just kill the process when it starts.
Or if your machines have Windows 7 (Windows 2008??) you can use AppLocker. http://www.microsoft.com/windows/enterprise/products/windows-7/features.aspx#applocker Just let Windows prevent the startup.
You might want to look at this product: http://www.sassafras.com/licensing.html Personally I can't stand it, but that's because it does what you describe. Might save you some coding.
You could actually edit the registry so when you click a psd, your launcher gets called instead of photoshop. Your launcher then checks for licenses and if there is one starts photoshop with the path of the file.
This is a long shot but you may find it helpful.
Perceived Types and Application Registration
http://msdn.microsoft.com/en-us/library/cc144150(VS.85).aspx
What is the best and cleanest way to close a console application on windows mobile?
The application by default is invisible and you cannot see it in the running programs, which is great for running a background process, but sometimes the user might need to close it..
Exit Main. Seriously. If you need someone to be able to exit is manually, there needs to be some mechanism like a shell icon and menu or a program in the Programs folder of something. How else would the user even know it's running? Any one of those visual cues would then set a named system event, and inside your Console app you'd have something listening for the same event (likely a worker). When it gets set, you take the actions required to shut down.
How would a user be able to close it if the application is not visible in the UI?
That's a great question. I once spent a long time trying to figure this out. Of course, we are assuming you can not (easily) return from Main. The correct answer on the desktop is System.Environment.Exit; But that method is conveniently not supported on CF.
An apparent second option is Application.Exit. That is on CF, but only applies to WinForms, and is in fact not guaranteed to exit your application.
So, throw an unhandled exception. ;)
EDIT: To kill it programatically from another app, you can look at Process.GetProcessById, and Process.Kill. Both of these are available on CF. You will have to somehow let the "killer" app figure out the "victim"'s ID. More convenient methods like Process.GetProcessesByName are not available on CF.
This technique isn't that elegant, though, and there may be permissions issues.
You could also consider some kind of IPC (inter-process communication), perhaps one overviewed in this previous Windows Mobile answer.
I decided to to read a boolean (keep alive) in the config file and have another application set it to false when I want to exit.
Its not that responsive but at least I can exit cleanly..