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- Disinfectant 1.5
- ================
-
- December 14, 1989
-
- Disinfectant 1.5 is a new release of our free Macintosh
- virus detection and repair utility.
-
- Shortly after the release of version 1.4, a new strain
- of the WDEF virus was discovered. Version 1.5 has been
- configured to recognize the new strain. Version 1.5
- also contains code to detect and repair other strains
- of WDEF which may exist but have not yet been
- reported.
-
- Disinfectant 1.5 is available now via anonymous FTP
- from site acns.nwu.edu [129.105.49.1]. It will also
- be available soon on sumex-aim, comp.binaries.mac,
- ComuServe, Genie, Delphi, BIX, MacNet, America Online,
- Calvacom, and other popular sources for free and
- shareware software.
-
- The following text is extracted from the new section
- on WDEF in Disinfectant's online document. It
- describes what we know to date about this new virus.
- The description has been expanded to include new
- information that has recently become available.
-
- The WDEF virus was first discovered in December, 1989 in Belgium
- and in one of our labs at Northwestern University. Since the
- initial discovery, it has also been reported at many other
- locations throughout the United States, so we fear that it is
- widespread. We have reason to believe that the virus has been in
- existence since at least mid-October of 1989. We know of two
- strains, which we call "WDEF A" and "WDEF B."
-
- WDEF only infects the invisible "Desktop" files used by the
- Finder. With a few exceptions, every Macintosh disk (hard drives
- and floppies) contains one of these files. WDEF does not infect
- applications, document files, or other system files. Unlike the
- other viruses, it is not spread through the sharing of
- applications, but rather through the sharing and distribution of
- disks, usually floppy disks.
-
- WDEF may have been introduced initially via a Trojan Horse
- application, in a fashion similar to the way the MacMag virus was
- first introduced via a Trojan Horse HyperCard stack. We do not yet
- know if this is indeed the case, and we may never know.
-
- WDEF spreads from disk to disk very rapidly. It is not necessary
- to run a program for the virus to spread.
-
- The WDEF A and WDEF B strains are very similar. The only
- significant difference is that WDEF B beeps every time it infects
- a new Desktop file, while WDEF A does not beep.
-
- Although the virus does not intentionally try to do any damage,
- WDEF contains bugs which can cause very serious problems. We have
- received reports of the following problems:
-
- * The virus causes both the Mac IIci and the portable to crash.
- * Under some circumstances the virus can cause severe performance
- problems on AppleTalk networks with AppleShare servers.
- * Many people have reported frequent crashes when trying to save
- files in applications under MultiFinder.
- * The virus causes problems with the proper display of font styles
- (the outline style in particular).
- * We have two reports that the virus can damage disks.
- * We have a report that the virus causes Macs with 8 megabytes of
- memory to crash.
- * We have a report that the virus is incompatible with the
- "Virtual" INIT from Connectix.
-
- Even though AppleShare servers do not use the normal Finder
- Desktop file, many servers have an unused copy of this file
- anyway. If the AppleShare administrator has granted the "make
- changes" privilege to the root directory on the server, then any
- infected user of the server can infect the Desktop file on the
- server. This is one of the situations which can lead to the severe
- performance problems mentioned above. For this reason,
- administrators should never grant the "make changes" privilege on
- server root directories. We also recommend deleting the Desktop
- file if it exists. It does not appear that the virus can spread
- from an AppleShare server to other Macs on the network, however.
-
- When using Disinfectant to repair WDEF infections, you must use
- Finder instead of MultiFinder. Under MultiFinder the Desktop files
- are always "busy," and Disinfectant is not able to repair them. If
- you try to repair using MultiFinder, you will get an error
- message.
-
- Unfortunately, when the WDEF virus first appeared, none of the
- current versions of the most popular virus prevention tools were
- able to detect or prevent WDEF infections. This includes Vaccine
- 1.0.1, GateKeeper 1.1.1, Symantec's SAM Intercept 1.10, and HJC's
- Virex INIT 1.12.
-
- Chris Johnson, the author of Gatekeeper, has released "GateKeeper
- Aid," a free system startup document (INIT) that detects and
- automatically removes WDEF infections and notifies the user of the
- infection. GateKeeper Aid can be used together with GateKeeper or
- together with Vaccine to provide protection against WDEF.
-
- New versions of the commercial tools should also be released soon,
- and we expect that at least one other free protection tool will
- also be available soon.
-
- It is very important that all Mac users obtain and install
- GateKeeper Aid or some other WDEF protection tool. You can use
- Disinfectant to remove an existing infection, but if you do not
- install a protection tool you may very likely become infected
- again.
-
- In addition to the two known strains of the WDEF virus,
- Disinfectant will also detect and repair other strains which may
- exist but have not yet been reported. If an unknown strain is
- detected, Disinfectant places the following message in the report:
-
- ### File infected by an unknown strain of WDEF
-
- If you see this message, and if you have not already repaired the
- file, we would appreciate it if you would send a copy to the
- author. The author's addresses are at the end of this document.
- You may need the assistance of an expert, since the Desktop files
- that are infected by the WDEF virus are normally invisible. You
- should use ResEdit or some other file editing tool to make the
- file visible, then make a copy to send to us, then use the same
- tool to make the original file invisible again, and use
- Disinfectant to repair it. Send the copy to the author, then
- delete the copy.
-
- Please do not worry if you are not comfortable with these
- instructions and you do not have access to an expert. Go ahead and
- repair the infected file. It is more important that you rid your
- system of the virus than it is for us to get a copy of the unknown
- strain.
-
- This version of Disinfectant is being released only one week after
- the discovery of the WDEF virus. We do not yet understand it as
- thoroughly as we do the other older viruses. We have disassembled
- it completely, and we understand the basic replication mechanism.
- We know that it can cause serious problems, and we know why it
- causes some of the problems. Research into the behavior and
- adverse effects of this virus will continue for some time.
-
- You should keep in touch with your local Mac user group or
- bulletin board for more information about this new virus as it
- becomes available. Commercial online services like CompuServe and
- Genie and the Macintosh trade press publications like MacWeek are
- also good sources of information.
-
- When the WDEF virus was first discovered, the authors of most of
- the popular virus-fighting programs and other experts immediately
- began working together to analyze and test the virus. The
- information presented here is a compilation of our joint
- discoveries. The author would like to thank everybody who helped
- in the investigation. Particular thanks to Chris Johnson
- (GateKeeper), Jeff Shulman (VirusDetective), Paul Cozza (SAM),
- Robert Woodhead (Virex), Dave Platt, Werner Uhrig, and the Apple
- Virus Rx team. Thanks also to the many Mac users who sent reports
- of WDEF sightings and problems caused by the virus.
-
- John Norstad
- Academic Computing and Network Services
- Northwestern University
- 2129 Sheridan Road
- Evanston, IL 60208
-
- Bitnet: jln@nuacc
- Internet: jln@acns.nwu.edu
- CompuServe: 76666,573
- AppleLink: A0173