How to remove BiFrost virus system32.exe

BiFrost virus system32.exe

Last Updated on Thursday, 07 January 2010 14:45 Tuesday, 22 December 2009 13:10

The file name system32.exe has appeared in an virus analysis report You can see the original report on this link

The virus is identified as a backdoor trojan Trojan Horse virus named Bifrose or BiFrost. It connects to remote hosts. It may further download more harmful files from the internet. A good firewall can make your computer much safer by detecting such harmful activities and blocking them. Some good freeware recommendations would be ZoneAlarm Free Firewall, and Comodo Internet Security Free Edition (you can choose to install just the firewall from their security suite)

It creates a hidden process iexplore.exe which is the name of internet explorer executable. So do not use Internet explorer till your computer is cleaned of the virus. It creates the file system32.exe on the infected computer. You need to search it and delete. You should end any running processes named system32.exe from Task Manager, and also remove the file's entries from windows startup.

There are several variations in the EXE file names used by this virus. I have grouped them together in BiFrost Family category

Statutory Warning: It is always possible that some legitimate application may be using the same file name as that of the virus, therefore to differentiate between the two, take into consideration the folder in which the file is located and also use special tools such as Windows Defenderand SysInternal Process Explorer to identify them.

Boot in safe mode

Sometimes you will not be able to delete a file even if you find it, in that case you should boot in safe mode and then try to delete it/ them.

How to boot in safe in windows XP

How to boot in safe mode in windows Vista

View Hidden Files

Before you could delete system32.exe and its associated files you need to search for them, and before doing that you need to enable to view hidden files and folders

How to Enable to View Hidden Files and Folders in Windows XP
- How to Enable to View Hidden Files and Folders in Windows Vista

Remove Processes from Task Manager

Press Ctrl Alt Del keys to open the Task Manager, then select Processes tab, in the list look for the name system32.exe select if found and press the End Process button. It will ask for your confirmation to end that process, select Yes. You can end one process at a time.

You can find out if a process appearing in your Task Manager is useful or harmful by using Windows Defenderto see the path of a currently running program/ process and its publisher, so as to differentiate malware processes from those belonging to legitimate publishers. You may find such processes listed under Unknown Publisher in windows defender.

How to use Windows Defenderin windows XP

How to use Windows Defenderin windows Vista

Or you can use Sysinternal's Process Explorer for easy detection and removal of virus processes.

How to use Sysinternal's Process Explorer

Removing entry from windows startup

The system configuration can be started in xp and in vista by typing msconfig in the run box/ start menu search box. In xp by clicking on Start > run . The windows startup is reversible, therefore you can check / uncheck any entry from windows startup any number of times.

After the system configuration window is open, Click on the Startup tab, that will list all the programs that are scheduled to start with windows. Expand the middle column using your mouse pointer so that you can see the full path of the program. Locate and uncheck "system32.exe" (look for any other suspicious names) Press Apply , Press Close/Ok , Select "restart" at the next prompt.

Deleting files

After restarting the computer, use the windows search utility to search for "system32.exe, server.exe " and also search for any other suspicious names listed below. This search should find all its folders on the hard disk, delete the folders from the hard disk. Boot in safe mode or in the dos prompt if needed.

These are the files created by this virus installer

C:\Documents and Settings\[UserName]\Application Data\addon.dat
C:\Windows\System32\system32\system32.exe
C:\Windows\System32\system32\klog.dat

and this folder

C:\Windows\System32\system32(this is a misleading folder name. Windows do not have a sub folder named system32 under C:\Windows\System32 folder)
Registry KeysSome of the registry keys will be automatically removed once you delete the virus files/ folders, and then run Registry menu of CCleaner.

Using CCleaner

Although you can easily get rid of the files in the temp folder simply by running a freeware like the CCleaner, and you will be much safer, if you set CCleaner to run automatically each time the computer starts.

Do not forget to run CCleaner > Registry menu to remove the obsolete registry entries.