Siemens Contract Programmer Faces Prison for Planting “Logic Bombs”

David Tinley, 62, was hired by a US division of Siemens, the German-based tech conglomerate, as a contractor to create custom automated spreadsheets that would help manage orders for electrical equipment. Today, he is facing up to 10 years in prison and a fine of up to $250,000.

So how does one go from freelancing spreadsheets to serving hard time?

According to the US Attorney’s Office of the Western District of Pennsylvania’s press release, Tinley pleaded guilty in federal court to a charge of intentional damage to a protected computer. He allegedly planted “logic bombs” in the spreadsheets, which are pieces of malicious code that disrupt the program when specific conditions are met, like a specific time on a specific date, explains Business Insider.

Tinley timed his logic bombs to go off every few years, which would cause glitches like error messages and size changes to on-screen buttons. When a glitch occurred, the company would call Tinley in to fix it, which he did by simply pushing back the date of the time bomb by another few years. 

Law360 reports that Tinley was caught when the system began glitching while he was on vacation after Siemens put an urgent order in. Since he was not in the office to fix it directly, he had to share his passwords that protected the system’s code with employees, revealing that the glitches were no accident.

Tinley’s lawyers argue that his motivation was solely to protect his proprietary work, as he never made any money by being hired to go in and fix the spreadsheets and thus was not trying to scam his own client. Prosecutors argue that Tinley’s actions exceeded the $5,000 in damages needed to label it a felony because Siemens spent about $42,000 on an investigation into possible damages. 

Tinley agreed to pay restitution for those costs and forfeit two laptops in his plea. His sentencing could add punishment such as the prospect of jail time and a fine.

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