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A contract programmer faces 10 years in jail for inserting a ‘logic bomb’ into a spreadsheet that caused the company to keep rehiring him

We’ve heard of programmers who secretly automated their jobs, but here’s a darker tale of a contract programmer who tried to force his employer to be dependent on him. Now, he’s facing up to 10 years in prison, as well as a fine of up to $250,000.

David Tinley, 62, pleaded guilty in federal court to a charge of intentional damage to a protected computer, the US Attorney’s Office of the Western District of Pennsylvania said in a press release.

Tinley had been hired by a US unit of Siemens, the German-based tech conglomerate, to create custom automated spreadsheets. The company used these spreadsheets to manage orders for electrical equipment.

Tinley planted “logic bombs” in the spreadsheets, the government alleged. Logic bombs are bits of malicious code that disrupt the program when specific conditions are met, like a specific time on a specific date.

In this case, the logic bombs were timed to go off every few years, the government alleged, causing the spreadsheet to experience glitches like error messages and size changes to on-screen buttons, according to a report from Law360.