Is there any way to hide a C# program from the Windows Task Manager?
EDIT: Thanks for the overwhelming response! Well I didn't intend to do something spooky. Just wanted to win a bet with my friend that I can do it without him noticing. And I'm not a geek myself to be able to write a rootkit, as someone suggested though I'd love to know how to do it.
Not that I'm aware of - and there shouldn't be. The point of the task manager is to allow users to examine processes etc.
If the user should be able to do that, they should be able to find your program. If they shouldn't be poking around in Task Manager, group policy should prevent that - not your program.
Don't mean to zombie this but i thought i could contribute some useful information
If you want to hide a application there a two methods (that i can think of atm).
They both have their ups and downs
[1] SSDT Table hooking - basically you have to set the MDL of the table to writeable, overwrite the address of NtQuerySystemInformation (iirc) with the address of your function and have it call the original function after filtering the results.
This method doesn't suit your needs very well because the hooking function would always need to be in memory and would involve writing a kernel mode driver. Its a fun thing to do but debugging is a pain because an exception means a BSOD.
[2] Direct Kernel Object Manipulation (DKOM) - the list of processes is a doubly linked list, with a kernel mode driver you can alter the pointers of the records above and below your process to point around yours. This still requires the use of a kernel mode driver but there are rootkits such as FU that can be easily downloaded that contain an exe and the service. The exe could be called from inside your application as a child process (in the released version of FU, at least the one I found, there was a bug which I had to fix where if the hidden application exited the computer would BSOD, it was a trivial fix).
This will thankfully be caught by almost any decent antivirus so if you are trying to do something sneaky you'll have to learn to get around that (hint: they use a binary signature)
I have not used method 1 ever but method 2 has worked for me from a VB.Net application.
A third possible option is to just create the application as a windows service, this will show up in task manager by default but I'm willing to bet that there is a way to tell it to not show up there since there are plenty of other services which don't show up in task manager.
Hope I helped a little, m