Even malware can produce silver linings — at least in the case of the Jerusalem virus, which inspired computer science students to develop some of the first antivirus software.

In November 1987, Omri Mann and Yuval Rakavi were computer science students at Hebrew University in Jerusalem. Mann noticed that whenever he ran a certain file on his computer, the program grew larger and larger in size. The friends remembered a story about Fred Cohen, a computer scientist at LeHigh University in Pennsylvania, who had publicly demonstrated how quickly malicious code could take control of a machine, earning such malware the name “virus.” The Israeli students realized they had a virus on their hands.

Jerusalem was a “logic bomb” that affected machines running MS-DOS. In addition to bloating programs, Jerusalem would delete all data on an infected machine — provided the date was Friday the 13th. Mann and Rakavi — as well as other Israeli computer scientists — began developing software to scan machines and identify those infected with Jerusalem. They distributed this software free of charge. (Learn more about Mann and Ravi in this episode of the podcast Malicious Life.)

Antivirus comes at a crucial time

Prior to the launch of antivirus software, a network administrator’s security options were few and far between, as evidenced by this October 1989 article from The New York Times. The article’s suggestion for combatting Jerusalem and other contemporary malware included sending everyone to the supply room after lunch to pick up a box of fresh diskettes so they could spend the afternoon backing up their data.

Still, this bit of wisdom remains timeless, whether you’re battling Jerusalem or the latest ransomware: “Backup, backup, backup. Make copies of all data files. If a company’s executives have not thought about computer security, at least they should have thought about disaster recovery. They should make absolutely sure that all the data in their computers are backed up.”

Jerusalem and its variants only ceased to be an issue in the mid-1990s when Windows supplanted MS-DOS as the primary operating system.

Photo:  Tero Vesalainen / Shutterstock.

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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