Neutering a Fake Antivirus Virus

Noah Petherbridge
kirsle
Posted by Noah Petherbridge on Thursday, May 26 2011 @ 10:42:07 PM
Tonight, my great aunt Connie needed some help with her computer. Normally, I don't do tech support for Windows users, but it was kinda too late to object to it because my grandma told her I'd be able to help her before even asking me. So I figured I'd just give it a look, tell her to what extent her computer is messed up, and tell her what she should do about it, and not break a sweat doing anything to actually help.

Luckily, this wasn't one of those typical, "I've installed eleven different PC cleaning programs and they all installed all kinds of malware and my computer takes two hours to boot and etc etc".

Instead, her only real concern was that when she logs on to the desktop, she gets this window popping up telling her the computer is infected with X amount of viruses, then it will pretend to scan your computer, and finally tell you to buy the full version to take care of the infections.

Yeah, one of those viruses.

I noticed that the desktop was solid black except for the task bar, and no icons were on the desktop. All that was visible on-screen was this one window. And, this window refused to close: it simply ignored the X button being clicked. I right-clicked on the task bar and noticed that "Task Manager" was greyed out.

Great, it's one of those viruses that disables Task Manager. Starting taskmgr from the Run dialog confirmed:

Task Manager has been disabled by your administrator.
I've seen the likes of these before. Usually, if a virus does this (and a lot of viruses do), they'll also disable your Registry Editor, so that you can't just go in and re-enable the Task Manager. I was expecting I'd need to write a program to fix the registry for me because Regedit would be disabled, and if so, this is where I would've called it a day.

Fortunately, the virus didn't stop me from getting into the Registry Editor. So, I went in and re-enabled Task Manager. I just had to make sure I deleted the following key from both HKEY_CURRENT_USER and HKEY_LOCAL_MACHINE (in this case, only the LOCAL_USER was affected by this and all the other registry changes).

\Software\Microsoft\Windows\CurrentVersion\Policies\System\DisableTaskMgr (1)
In Task Manager, I first killed off that GUI, and a couple other suspicious looking names.

Back in the Registry, I went to the Run and RunOnce keys in both places to find the name of the virus (viruses always place their keys in these places in the registry). It turns out this virus's main EXE file was under C:\Documents and Settings\All Users. So, I went there in Windows Explorer.

This folder was completely empty. OK, the files were all hidden, so I went into the Folder Options to enable the "Show hidden files/folders" option. There they are! I saw the hidden EXE's that this virus was running off of. After a few seconds, all the icons disappeared again. Clever virus! It changed my "Show hidden files/folders" option back off again.

I turned it back on, and deleted these files. Then, I rebooted the computer (since I removed all the startup keys--and made sure I looked in the "Startup" folder of the start menu)--the viruses weren't likely to start back up after a reboot. I was right. Virus has been neutered. Now I had to clean up the damage.

First, I had to fix the desktop. The virus had disabled right-clicking on the desktop, disabled desktop icons, and disabled the ability to set the desktop wallpaper. I had to fix this by deleting these keys from the registry (again, only under CURRENT_USER, but check for LOCAL_MACHINE too if this ever happens to you):

\Software\Microsoft\Windows\CurrentVersion\Policies\Explorer\NoViewContextMenu (1)
\Software\Microsoft\Windows\CurrentVersion\Policies\Explorer\NoDesktop (1)
\Software\Microsoft\Windows\CurrentVersion\Policies\ActiveDesktop\NoChangingWallpaper (1)
This let me restore the desktop to its original glory. Then, I noticed the Start Menu was just absolutely empty. There were no "recently used" apps in the menu, and when I moused over the "All Programs" link, I just got a small pop-up menu that said "(empty)"

So I right-clicked the Start button to "Explore", and noticed that all the start menu folders were marked as hidden. This was done in the local user account and the "All Users" folder. So, I un-hid all these folders to bring back the start menu items. But, this virus did something even more evil than that: it deleted every shortcut file from the Start Menu.

So, we got all the folders back in the Start Menu, but every folder was empty. Like, "Start->All Programs->AOL Instant Messenger->(empty)".

This virus really went to great lengths to make my great aunt's life more difficult. I neutered it and undid most of the damage, but there's no automatic way to restore the Start Menu shortcuts. Plus, I noticed that many of the programs mentioned in the Start Menu aren't even installed anymore at all. Maybe the virus actually deleted as many programs from the computer as it could? The only programs in "C:\Program Files" were core built-in programs that come with Windows (speaking of which, every folder in C:\Program Files was marked Hidden as well!)

If this was my computer, I'd reinstall the OS. But it's not, and I'm not getting paid for any further tech support, but figuring out what extent this virus messed up the system was fun enough in itself.

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Comments

There are 4 comments on this page.

guest
guest
Posted on Saturday, May 28 2011 @ 11:11:12 AM by matt.

and you have to ask yourself, why would microsoft even design windows so that programs have the capability of disabling the task manager and hiding desktop icons i cant imagine a single legitimate reason for ANY program to ever hide all your deskop icons, it's absurd that viruses are able to change these registry keys

guest
guest
Posted on Monday, June 20 2011 @ 02:13:51 PM by Anonymous.

http://www.pcmech.com/forum/networking-online-security/220860-solution-missing-start-menu-shortcuts.html

guest
guest
Posted on Friday, August 19 2011 @ 12:52:27 PM by Krista.

Ok, I HATE my PC. But I can't just toss it for a Mac until I have saved enough $$$. THis virus sounds exactly like what I am going through. Exepct it has also denied access to my c:/ any ideas on how to overcome that?

guest
guest
Posted on Saturday, October 20 2012 @ 01:54:12 AM by anon.

@matt

Maybe if you actually thought about it you would realize that those are features that are used. Businesses and schools need to have the ability to lock down systems from both a hardware and software perspective. There are more reasons as well, just research it...

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