I want to run an Application at system startup.
I know it will run under Session 0.
I want System-Wide (works for All Users) Hotkey
This Hotkey Shows/Hides a GUI that is populated by the Application
As an example, Deepfreeze by Faronics does this exact thing. It runs under Session 0 and no matter which user you log in as you can press CTRL ALT SHIFT F6 and bring up a GUI. I know Deepfreeze is not .NET just fyi.
Who among you knows how to replicate this scenario?
You need to have two processes, this is how system services operate. The first process is the service itself. The second process is the GUI and it is started when a user logs in to Windows. Then these two processes communicate using named pipes or any other inter process communication means.
I recommend you to read a few chapters of any book devoted to services programming, because this is very basic information you find there.
Related
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/
For practical purposes but also as a learning exercise, I am wanting to create notification application to remind me of friend's Birthdays. I would like the application to be running in the background so that it can check the current date against user configured reminders. If a reminder is due then the user is displayed a simple Window that will allow them to snooze or dismiss the notification. I want the application to have user specific notifications (i.e. User A's notifications are not seen when User B is logged in).
Option 1 - Application launched upon Windows startup:
I thought about keeping it simple by checking when to display notifications only when the application starts up. I would then put a shortcut in the Windows Startup folder. However, this probably wouldn't work if the PC is put to sleep and resumed each day.
Option 2 - Application constantly running in background:
I then thought about making the application so it minimises to an icon in the System Tray and thus would constantly be running in the background. It would then periodically check when to display notifications.
Option 3 - Using Windows Service with application:
I then thought about using a Windows Service to do the periodic checks as to when to display notifications. Obviously, a Windows Service cannot display UI notifications so it would need to use some other mechanism for notification (e.g. sending an email). An application could then be used to configure settings that the service uses.
Are there any other options that I have not considered which would work better. I'm currently inclined to go with option 2 for my first implementation but could look to move to a better solution afterwards.
TIA
Your option 2 is the optimal one since you are aimed to distinct users and their reminders - your application runs in the context of a particular user, you already know which remainders need to be shown. Of course, you could go for the third option but this way is really need more time to code and the code itself would be more complex. I would go for the second option. As your applications is WinForms, for the periodical checks I would recommend you to use System.Windows.Forms.Timer class.
By the way, showing an icon in the tray notification area does not make your application "run in the background", it is just a convenient way to show your application is up and running.
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.
I'm writing a software for a call-center. It's somewhat like a ATM program: user can only interactive with it, not with underlying Windows. It takes controls when user logs in to Windows, and when user exits, it logs off Windows.
How can I do that in .NET? A demo will be much appreciated.
Thank you.
Replace the Windows Shell.
By that I mean Explorer.exe, by means of editing the Windows Registry. What this does for you is instead of logging on and the system running Explorer.exe which consists of the Start Menu, Taskbar and other similar features you are familiar with, it only runs your program. There is no desktop, no context menu, no taskbar, or start menu. Thus, making your application "The Shell" or the new "Explorer.exe".
However, by doing this the user still has access to Control+Alt+Delete, so they would still be able to access the Windows Task Manager, which mind you can also be disabled via a simple Registry Key Entry.
This is the most pain free, easiest solution because you don't even have to worry about things such as disabling the WindowsKey or other annoyances.
The registry key to this is as follows:
SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon
The name of the value to modify is:
Shell
And you can simply enter the value to be the fully qualified path to your program's executable file. You will only want to do this under HKEY_CURRENT_USER and only for the account that is to run your shell program. So you will need two separate accounts.
Administrator account
This account will just be a normal password protected account that will be used to manage the system
Kiosk account
This account will be the account that is logged on at all times, which runs your custom shell (your application)
Additional Notes
To disable the Task Manager the registry path is as follows:
Software\Microsoft\Windows\CurrentVersion\Policies\System
The name of the value is:
DisableTaskMgr
This is a DWORD value which to enforce the policy must be set to '1'.
What I did was to use DirectX and just use full-screen and exclusive modes, which you can see a small example of here: http://www.directxtutorial.com/tutorial9/b-direct3dbasics/dx9B2.aspx.
This is more work, but it will allow you to do what you want.
Depending on what control you have, there are steps you can do with group policy to limit what people can do on the computer. You can look at how people set up a kiosk application on Windows for some ideas.
What you want to do is run the OS in "kiosk mode".
This entails using the Group Policy Management Console to apply the kiosk mode template - as part of this you register your application as the shell.
As such there is no taskbar, or explorer view to fall back on to. The only way to run the usual shell would be to connect a keyboard to the system - press ctl-alt-delete and run explorer from the taskmanager that pops up.
And you can disable even the standard task manager if users are going to have keyboard access to the console. You will want to implement some kind of launch explorer.exe interface otherwise the system might become a bit difficult to manage :P
You can set your applications window to be always on top and to cover the entire screen. If you exclude buttons that close the window the user must know that ALT+F4 closes the window in order to exit. This has been good enough for me those times I've needed it.
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