Threat Description



Category: Malware
Platform: W32
Aliases: Quox


The Quox virus is a reasonably simple diskette and Master Boot Record infector. It is only able to infect a hard disk when you try to boot the machine from an infected diskette. At this time Quox infects the Main Boot Record, and after that it will go resident to high DOS memory during every boot-up from the hard disk.


Automatic action

Once detected, the F-Secure security product will automatically disinfect the suspect file by either deleting it or renaming it.

More scanning & removal options

More information on scanning or removal options is available in the documentation for your F-Secure security product on the Downloads section of our Home - Global site.

You may also refer to the Knowledge Base on the F-Secure Community site for more information.

Contact Support

For further assistance, F-Secure customers can request support online via the Request support or the Chat forms on our Home - Global site.

Technical Details

Once Quox gets resident to memory, it will infect practicly all non-writeprotected diskettes used in the machine. Quox-virus is also a stealth virus - if you try to examine an infected boot record, it will show you the original clean one instead.

Quox-virus has no particular payload and no text strings. It does not activate in any way, but it will corrupt some diskettes seriously. The damage might not be visible as long as the virus is resident in memory because of the stealth. When infected diskettes are used in a clean machine, they will typically be unreadable and, due a bug in DOS, may even crash the machine.

Virus was found in Thailand in July of 1992. Virus was named to be "Quox" at the IBM High Integrity Labs because "there was no obvious good name, and we didn't have very many viruses starting in 'Q'", David Chess from IBM commented.

Description Details: Mikko Hypponen, F-Secure


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