There are no significant differences between the two strains.

There are two known strains of the MBDF virus, MBDF A and MBDF B.



products.

strongly encourage other vendors to consider doing the same with their

detection of the virus, and has thus helped the entire Mac community.  We

Macintosh software products.  Their foresight resulted in an early

Special thanks to the people at Claris who included self-check code in their



not become alarmed if you see them with ResEdit or some other tool.

MBDF resources are a normal part of the Macintosh system, so you should

The MBDF virus is named after the type of resource it uses to infect files.



problems on infected systems.

“BeHierarchic” shareware program, and reports of other menu-related

We also have reports that the MBDF virus causes problems with the



to reinstall a new System file from scratch.

System file which cannot be repaired. The only solution in this situation is

the process of writing the System file very often results in a damaged

Mac is hung, so they do a restart. Restarting the Mac while the virus is in

attacks a system. The delay is so long that people often think that their

the virus takes quite a long time to infect the System file when it first

The MBDF virus is non-malicious, but it can cause damage. In particular,



become infected as soon as they are run on an infected system.

is infected as soon as an infected application is run. Other applications

usually infects the Finder and several other system files. The System file

The MBDF virus infects both applications and the System file. It also



the Trojan horse renders it ineffective and inoperable.

and returns the file to the state it was in before being infected. Repairing

infected by the MBDF virus. Repairing an infected file removes the virus

VirusScan identifies both infected files and the Trojan horse as being



service.

charge for helping to spread the virus, and was sentenced to community

restitution of damages. A third student at Cornell also pleaded guilty to a

spreading the MBDF virus. They were sentenced to community service and

to charges of second-degree computer tampering for writing and

apprehended shortly after the virus was discovered. They pleaded guilty

Two undergraduate students at Cornell University were quickly



“tetris-rotating” was a Trojan horse which installed the virus.

In addition to these two games, a third game named “Tetricycle” or



games were named “10 Tile Puzzle” and “Obnoxious Tetris.”

period of time, so a number of people around the world were affected. The

popular Internet archive sites contained some infected games for a short

The MBDF virus was first discovered in Wales in February, 1992. Several




xThe MBDF Virus