It lists 72 different organisations that were targeted over five years, including the International Olympic Committee, the UN and security firms.

Speaking to BBC News, McAfee's chief European technology officer, Raj Samani, said the attacks were still going on.

Dubbed Operation Shady RAT - after the remote access tool that security experts and hackers use to remotely access computer networks - the five-year investigation examined information from a number of different organisations which thought they may have been hit.

"The United Nations, the Indian government, the International Olympic Committee, the steel industry, defence firms, even computer security companies were hit," he added.