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Christma ExecAs an MSP, you might want to remind clients not to let holiday cheer get in the way of smart Internet use and security best practices. Thirty years ago, users of the European Academic Research Network (EARN) and its U.S. equivalent BITNET found their networks clogged by the CHRISTMA EXEC, also known as Christmas Tree.

The creation of a German graduate student, CHRISTMA EXEC (“CHRISTMA” because file names were limited to eight characters at the time) was a script that ran under the Rexx language. Arriving with the subject line “Let this exec run and enjoy yourself!” (alarms going off yet?), the script displayed a charming ASCII image of a Christmas tree and holiday greetings—as it forwarded itself to everyone in a user’s address book. The only way to stop CHRISTMA was to shut down an entire network.

Ghosts of CHRISTMA EXEC past

After its December 1987 debut, CHRISTMA EXEC resurfaced in 1990 on IBM’s internal VNET, 350,000 terminals strong. Again, the only solution was a network shutdown.

The moral of the story? The only way to spread Christmas cheer might be singing loud for all to hear—but the dark forces of the Internet are all too ready to spread their handiwork under the guise of season’s greetings. Keep your guard up, and happy holidays!

Photo: Gajus/

Tech Time Warp is a weekly feature that looks back at interesting moments and milestones in tech history.

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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.

One Comment

  1. Thirty years and if nothing else it has become even more prevalent and now it’s even profitable. The roots of human social engineering go very deep in the psyche.


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