Ruby and Zev were classmates but didn’t get along well. One weekend, shortly before a test, Ruby asked to borrow Zev’s notes and kept them the entire weekend, ignoring Zev’s pleas to return them. Not surprisingly, Zev did poorly on the test. He decided to get back at Ruby.
Two days later, Ruby received an e-mail from Ruby, with the subject heading “Helpful computer program.” Attached was an .exe file, with a message to click on the file to install the program.
“That was nice of Zev to share the program with me,” Ruby said to himself. “I thought he was really mad at me.”
Ruby clicked on the file. He expected an installation dialogue box to open. Instead, after a minute, his screen went blank.
“What just happened?” Ruby exclaimed aloud.
He pressed various buttons on the keyboard but received no response. “Let me try rebooting,” Ruby said. He shut the computer and restarted it, but Windows didn’t load. The screen just sat there blank.
“Could it be that the file was a virus?” Ruby wondered. “I can’t believe that Zev would do this just before the Yamim Noraim! In any case, I’m going to have to take the computer to the technician.”
Ruby removed all the wires and cables from the computer and brought the computer in. “The computer suddenly stopped working after opening an e-mail attachment,” he said to the technician. “I suspect the file might have been a virus.”
“There are lots of those going around,” said the technician. “Do you have an anti-virus installed?”
“Of course,” replied Ruby. “I downloaded one of the free versions.”
“They’re not 100 percent effective,” said the technician. “I’ll have a look and see what I can do. Write your phone number on this card, and I’ll call you when I identify the problem.”
Ruby went home. Later that day, the technician called. “You got hit by a new virus,” he said. “After a few hours of work, I was able to remove it and get the system started. Some files got erased; I hope you have some backup. It comes to $350 for the repair.”
Ruby thanked the technician. “I’ll be over to pick up the computer,” he said.
On the way there, Ruby thought about what happened. “It’s Zev’s fault for sending this virus,” he reasoned. “I’ll bet he’s liable for the repair.”
Ruby called Rabbi Dayan and asked: “Is someone liable for the damage he caused by sending a virus as an e-mail attachment?”
“Before addressing the liability of someone who sends a virus as an attachment, we need to clarify the status of a computer virus,” answered Rabbi Dayan. “The analogy to classical cases of damage is a fascinating subject of discussion. The Mishnah in the beginning of Maseches Bava Kama (2a) mentions four categories of damage: damage inflicted by one’s animal, by an obstacle he placed, by the person himself, and by a fire he lit.”
“What category would a computer virus fall under?” asked Ruby.
“Some compare the computer virus to aish, a fire that spreads beyond control,” replied Rabbi Dayan. “Like a fire, the virus is generated in the sender’s computer, and then spread over the Internet, though e-mail, contact books, and other media. This might lead to consideration of various limitations of aish, such as items that are “concealed” and distinctions between the initial recipient and subsequent recipients.” (See Techumin, vol. 22, pp. 325-333)
“That sounds reasonable,” said Ruby.
“Others consider the virus similar to an obstacle, bor,” said Rabbi Dayan. “Although bor is typically characterized by a damaging item that is stationary, the Gemara derives liability also for an obstacle that is tossed or kicked around inadvertently by the wind, an animal, or people. In halacha this is called bor hamisgalgel. This would provide a significant limitation, though, since there is a legal exemption of bor for inanimate items (keilim) such as a computer.”
“Finally, some consider the virus a direct action of the person who sent it, similar to person who shoots an arrow or uses a hammer to break something,” said Rabbi Dayan. “Here, too, the person uses the medium of the computer to send the damaging virus.” (See Techumin, vol. 24, pp. 102-109)