Hackers have stolen a ton of data from an IT company whose clients include Oracle, Airbus, and Porsche

Porsche

Porsche is among Citycomp's clients.

• Hackers have stolen a ton of data from German IT company Citycomp, whose clients include multinationals including Oracle, Airbus, and Porsche.
• Motherboard first reported the story, and got confirmation of the hack from a cybersecurity executive authorised to speak about the matter.
• The hackers set up a website threatening to publish sensitive financial information, but it's not clear what they are demanding from Citycomp.
• Visit Business Insider's homepage for more stories.

Hackers are blackmailing a massive German IT company with stolen data on some of the world's biggest companies, Motherboard reports.

The hackers created a website in which they claimed to have stolen "over 516GBb data financial and private information on all clients" from IT services provider Citycomp. The firm reportedly has some notable clients on its books, including Oracle, Airbus, Hugo Boss, Porsche, and Volkswagen.

Michael Bartsch, executive director of cybersecurity firm Deutor, which Citycomp said was authorised to speak about the attack, confirmed to Motherboard that the hack had taken place.

"Citycomp has been hacked and blackmailed and the attack is ongoing," Bartsch said. "We have to be careful as the whole case is under police investigation and the attacker is trying all tricks."

Read more: McDonald's app customers are getting their accounts hijacked by hackers who spent as much as $2,000 on enormous orders of Big Macs and nuggets

Bartsch added that all affected clients were informed of the attack, and that the company has not given in to the attackers' extortion attempts.

"We did not yield to the extortion demands and our analysts are conducting a profound technical and forensic analysis on the attack," he said. It is not clear how what the hackers are demanding.

The website reportedly said it would make the stolen files public on April 31, but as Motherboard's Joseph Cox points out, there is no April 31.

Cox noted that the stolen data was not accessible, and that clicking on the files yielded "403 forbidden" messages. He was, however, able to see the lists of files and their names, many of which suggest the files contain finance-related spreadsheets.

Citycomp was not immediately available for comment when contacted by Business Insider.