Summary

W-boot is a stealth boot sector virus that infects MBRs on hard drives and floppy boot sectors. It allocates 1kB of memory.

The virus will only infect hard drives when an attempt to boot from an infected diskette is made. Once the virus has infected the hard drive, all non-protected floppies used in the machine will be infected.

Additional Details

W-boot uses stealth routines, so it cannot be found from boot sectors when it is active in memory. F-Secure anti-virus products detect if W-boot is resident, and will advise you to boot from a clean diskette.

W-boot contains no texts and has no activation routines.

Some programs also detect the W-boot virus as EXEBUG, but this virus is not related to ExeBug at all.

There are three known variants of this virus. W-Boot was known to be in the wild in Luxembourg in April 1995.

[Analysis: Pierre Vandevenne, DataRescue sprl & Mikko Hypponen, F-Secure] .