While usual strains of ransomware lock down a user's files in exchange for a monetary ransom, a new brand of malware is forcing victims to beat a ridiculous high score in an anime shooter to decrypt their files. Dubbed Rensenware, the ransomware forces users to play the bullet hell shooter Undefined Fantastic Object and score over 200 million on the game's "Lunatic" level to retrieve their data.
Created by a Korea-based student as a joke, Rensenware is a pun on the 2009 shooter's Japanese title - Touhou Seirensen. According to Malware Hunter Team, Rensenware presents its victims with a warning message alongside an image of an anime sailor girl that reads: "Minamitsu 'The Captain' Murasa encrypted your precious data like documents, musics, pictures, and some kinda project files."
"This application will detect TH12 process[es] and score automatically," the warning continues and cautions victims not to try and cheat or terminate the application. A gameplay video of the Japanese shooter is embedded below.
However, Kotaku reports that Rensenware was actually released by its creator, who goes by the name Tvple Eraser on Twitter, onto GitHub as a joke before it quickly spread.
The student told Kotaku that he "was bored" and fell asleep after releasing the malware onto GitHub. He later found out that it had spread and "realized that it [had] become a huge accident."
He said also accidentally infected his own computer in the programming process and could not beat the impossible score either.
He quickly designed a tool to neutralize the ransomware that lets you bypass Rensenware's forced encryption, manipulate the game's memory and skip playing the game altogether in case you happened to get infected. The tool has been uploaded to GitHub along with an apology for releasing the "highly-fatal malware." He has also taken down the original Rensenware source code and replaced it with a new "cut" version without the forced encryption.
"I'd like to apologize [to] everyone for making [them] shocked or annoyed. Ransomware is definitely kind of highly-fatal malware, but I made it," Tvple Eraser wrote. "I made it [as a] joke, and just laughing with people who like Touhou Project Series.
"A number of people blamed me. It's natural," he continued. "I'm not sure this apology is enough to you. If not, then I apologize again... It didn't [mean] to be evil. I hope you understand."