Oleg Pliss is a ransomware on iOS. It is believed to originate from either Russia or USA. It appeared across Australia and New Zealand, demanding ransoms ranging from 50-100 dollars. The attack may not have been malware, but instead, a data breach leaking Apple IDs and passwords, allowing hackers to access Apple accounts remotely.
The alleged Oleg Pliss hackers originated from Russia and were possibly arrested in 2014. There is an article claiming this had happened. https://threatpost.com/alleged-oleg-pliss-iphone-hackers-arrested-in-russia/106570/