### File infected by an unknown strain of WDEF



following message in the report:

been reported. If an unknown strain is detected, Disinfectant places the

also detect and repair other strains which may exist but have not yet

In addition to the two known strains of the WDEF virus, Disinfectant will





you try to repair using MultiFinder, you will get an error message.

files are always “busy,” and Disinfectant is not able to repair them. If

must use Finder instead of MultiFinder. Under MultiFinder, the Desktop

When using Disinfectant to repair WDEF infections under System 6, you



is cause for concern.

operating system. Any WDEF resource in a Finder Desktop file, however,

Finder Desktop files. WDEF resources are a normal part of the Macintosh

resources, do not be alarmed if you find them in files other than the

If you use ResEdit, VirusDetective, or some other tool to search for WDEF



from a TOPS client to a TOPS server.

infected volume. It does not appear, however, that the virus can spread

published volume’s Desktop file is infected and the client mounts the

The WDEF virus can spread from a TOPS server to a TOPS client if a



server to other Macs on the network, however.

it exists. It does not appear that the virus can spread from an AppleShare

on server root directories. We also recommend deleting the Desktop file if

reason, administrators should never grant the “make changes” privilege

performance on the network will be very severely degraded. For this

the Desktop file on the server. If a server Desktop file becomes infected,

directory on the server, then any infected user of the server can infect

administrator has granted the “make changes” privilege to the root

file, many servers have an unused copy of this file. If the AppleShare

Even though AppleShare servers do not use the normal Finder Desktop



System 7.

Disinfectant. This is also the only way to get rid of a WDEF infection under

of a WDEF infection by simply rebuilding the Desktop file than it is to use

See the “Problem Clinic” section for details. It is often easier to get rid

You can remove a WDEF infection from a disk by rebuilding the desktop.



proper functioning of your Macintosh.

that the errors in the virus can cause almost any kind of problem with the

font style. Many other symptoms have also been reported and it appears

font styles. In particular, it often causes problems with the “outline”

damage disks. The virus also causes problems with the proper display of

causes other Macs to crash much more frequently than usual and it can

insertion of an infected floppy (the IIci and later models). The virus also

virus causes newer Mac models to crash almost immediately after

contains errors which can cause very serious problems. In particular, the

Although the virus does not intentionally try to do any damage, WDEF



whereas WDEF A does not beep.

difference is that WDEF B beeps every time it infects a new Desktop file,

The WDEF A and WDEF B strains are very similar. The only significant



Fortunately, System 7 is completely immune to the WDEF virus.



application for the virus to spread.

WDEF spreads from disk to disk very rapidly. It is not necessary to run an



through the sharing and distribution of disks (usually floppy disks.)

viruses, it is not spread through the sharing of applications, but rather

applications, document files, or other system files. Unlike the other

under System 6 contains one of these files. WDEF does not infect

few exceptions, every Macintosh disk (hard drives and floppies) used

WDEF only infects the invisible “Desktop” files used by the Finder. With a



and “WDEF B.”

is very widespread. We know of two strains, which we call “WDEF A”

has also been reported at many other locations, and we now know that it

one of our labs at Northwestern University. Since the initial discovery, it

The WDEF virus was first discovered in December, 1989 in Belgium and in




xThe WDEF Virus