If you’re in any doubt as to the rising popularity of ransomware, here’s today’s second piece of news related to the malicious software: It’s been reported that the malware was used to prevent guests accessing their rooms at a luxury hotel after it infected the resort’s electronic key system.

Romantik Seehotel Jägerwirt, a four-star hotel in the Austrian Alps, ended up paying attackers $1600 to release its paralyzed systems, according to owner Christoph Brandstaetter. Initial reports stated that guests were locked inside their rooms, but this wasn’t true.

Motherboard writes that the 180 guests who had checked in before the attack were able to get in and out of their rooms thanks to the internal system, which wasn’t networked with the infected computers. However, no new keycards could be issued to the guests checking-in during the 24-hour period that the reservation system was down, leaving no option but to hand over the ransom.

“The police told us that we are one of many companies hacked recently,” Brandstaetter said. “They are trying to figure out who made the cyberattack.”

The incident marks the third time in under a year that the hotel has been hit with ransomware. The frequency suggests that the attackers have been leaving backdoors on the system that allow them to mount new attacks whenever they need more cash.

Brandstaetter said that system upgrades had been installed, preventing what would have been a fourth attack. But just to be sure, he plans to change the hotel’s locks to “old-fashioned locks with real keys” when it undergoes its next refurbishment.

“We made it public because we have many colleagues and other companies who have had these cyberattacks,” Brandstaetter said. “It's not just our hotel at all.”