Since 2011, Iran has worked to establish itself as a prominent aggressor in cyberspace, alongside China, Russia and North Korea. Evolving from mere website defacement and crude censorship domestically in the early 2000s, Iran wasn’t pursuing cyber capabilities with much urgency, experts say, until it was revealed in 2010 that a joint Israeli-U.S. Stuxnet worm sabotaged nuclear centrifuges at Iran’s facility in Natanz Cipher Brief

Cybersecurity isn't easy, but simple principles still apply. Accountability is one, cooperation another. They are the cornerstones of security and resilience in any society. In furtherance of both, and after careful investigation, the U.S. today publicly attributes the massive "WannaCry" cyberattack to North Korea.

The attack spread indiscriminately across the world in May. It encrypted and rendered useless hundreds of thousands of computers in hospitals, schools, businesses and homes. While victims received ransom demands, paying did not unlock their computers. It was cowardly, costly and careless. The attack was widespread and cost billions, and North Korea is directly responsible.Wall Street Journal

Kaspersky Security Bulletin. Overall statistics for 2017 https://www.kaspersky.com/images/KESB_Whitepaper_KSN_ENG_final.pdf