[comp.virus] Alameda/Yale

Michael_Kessler.Hum@mailgate.bitnet (02/09/91)

Someone just brought in 3 diskettes, 2 of which contained only text
files, the last one contained an application.  None of them were boot
diskettes (although they may have been originally and someone simply
erased the command.com file).  F-Prot's (version 1.13) F-Disinf
claimed that all three had the Alameda/Yale virus.  But when asked to
clean the boot sector, I received that message that the virus could
not be removed, no boot sector was found.  Copying the files to a new
disk and reformatting the disks solved the problem. But is there any
explanation for finding the virus in an infected boot sector that then
cannot be found?

frisk@rhi.hi.is (Fridrik Skulason) (02/10/91)

Michael_Kessler.Hum@mailgate.bitnet writes:
>But when asked to clean the boot sector, I received that message that the
>virus could not be removed, no boot sector was found.  Copying the files to
>a new disk and reformatting the disks solved the problem. But is there any
>explanation for finding the virus in an infected boot sector that then
>cannot be found?

The diskettes are infected, all right - the problem is just that the
original boot sector, (which is normally stored on track 39) cannot be
found.

This could be because the diskettes did not contain a valid boot
sector when they were infected - the disinfector could remove the
virus, but when it attempts to locate a valid boot sector to replace
it with, it fails.

Another possibility is that the diskettes were infected by a new
variant of the virus, (which stores the boot sector elsewhere) but
this cannot be determined as the diskettes were (unfortunately)
formatted.

- -frisk

Fridrik Skulason      University of Iceland  |
Technical Editor of the Virus Bulletin (UK)  |  Reserved for future expansion
E-Mail: frisk@rhi.hi.is    Fax: 354-1-28801  |