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Tech Time Warp

It’s the most wonderful time of the year! That doesn’t mean you should let your guard down when it comes to cybersecurity. That’s a lesson some computer users learned the hard way in December 1987. In this edition of Tech Time Warp, you’ll see how, instead of glad tidings, the CHRISTMA EXEC virus brought the need for network shutdowns.

Created by a West German graduate student, CHRISTMA EXEC, aka Christmas Tree, was a script. It was written in the general-purpose Rexx programming language. Ostensibly created as somewhat of an early e-card to spread holiday cheer, the malware (more appropriately categorized as a Trojan) displayed a cute ASCII Christmas tree image while simultaneously replicating itself through messages sent to everyone in the infected computer’s address book. The virus traveled with the ominous subject line “Let this exec run and enjoy yourself!”. The quick replication bogged down network traffic.

The European Academic Research Network (EARN) and its U.S. counterpart, BITNET, had to shut down when their networks were clogged by CHRISTMA—as did the 350,000 terminals of IBM’s internal VNET when the virus reappeared in 1990.

The missing “s” at the end of the exec’s name wasn’t a typo. At the time, file names were limited to eight characters.

As the Oct. 15, 1990, issue of the Computer Underground Digest states: “A word of warning: IBM users should be extremely cautious of *ANY* EXEC that simply appears in their reader.”

Did you enjoy this installation of SmarterMSP’s Tech Time Warp? Check out others here.

Photo: Pasko Maksim / Shutterstock

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Kate Johanns

Posted by Kate Johanns

Kate Johanns is a communications professional and freelance writer with more than 13 years of experience in publishing and marketing.

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