Classification

Category :

Malware

Type :

Virus

Aliases :

Urkel, NWait

Summary

This virus infects the Master Boot Records of hard disks and the DOS boot records of diskettes. It spreads only through diskettes.

Removal

Based on the settings of your F-Secure security product, it will either move the file to the quarantine where it cannot spread or cause harm, or remove it.

A False Positive is when a file is incorrectly detected as harmful, usually because its code or behavior resembles known harmful programs. A False Positive will usually be fixed in a subsequent database update without any action needed on your part. If you wish, you may also:

  • Check for the latest database updates

    First check if your F-Secure security program is using the latest updates, then try scanning the file again.

  • Submit a sample

    After checking, if you still believe the file is incorrectly detected, you can submit a sample of it for re-analysis.

    Note: If the file was moved to quarantine, you need to collect the file from quarantine before you can submit it.

  • Exclude a file from further scanning

    If you are certain that the file is safe and want to continue using it, you can exclude it from further scanning by the F-Secure security product.

    Note: You need administrative rights to change the settings.

Technical Details

Urkel does not let the original partition table remain in its proper place in the Master Boot Record, as most other MBR viruses do. This causes the hard disk to be inaccesible after a floppy boot, since the operating system cannot find valid partition data in the Master Boot Record - attempts to use the hard disk result in the DOS error message "Invalid drive specification".

When the computer is booted from the hard disk, the virus is executed first, and the hard disk can thereafter be used normally. The virus is not, therefore, easily noticeable, unless the computer is booted from a diskette.

Do not use FDISK /MBR to clean Urkel: you will loose all your data.

Note: When disinfecting Urkel with F-PROT after a floppy boot, use the command F-PROT /HARD /DISINF instead of using F-PROT C:, or just run F-PROT in interactive mode and scan 'Hard disk' with disinfection option on. After disinfection, error message 'No hard disk found' is normal: just reboot after the disinfection is done and you should see your hard drive again.

Urkel virus sometimes displays text 'Urkel' on screen.