But questions later surfaced about whether the airline was actually attacked or something less sinister was going on.
Based on statements from the airlines and information from other sources, here's what happened:
In the aftermath of the problem, security experts raised questions on Twitter about the attack as it had been outlined by LOT. To them, it sounded more like a minor issue caused by someone improperly using the airline's systems -- not a full-fledged cyberattack.
Even if the problem turns out to be minor, concerns about airline safety and cybersecurity continue to arise. Earlier this year, for instance, the FBI contended that cybersecurity researcher Chris Roberts caused an airplane's engine to climb after hacking its software. (Roberts wasn't charged, but United Airlines banned him from its flights.)
With reports from Darlene Storm at Computerworld.