Powerful tools used by nations to spy on one another falling into the hands of cyber criminals, and malicious software breaching protected targets such as power grids and banks.
These were among case studies highlighted yesterday at a conference where 200 law enforcement officials, private sector specialists and academics from 56 countries discussed the growing threat of cybercrime and how best to tackle it.
And in a more interconnected world, individuals and companies are not spared, said Mr Philipp Amann, acting head of strategy at the European Cybercrime Centre, Europol (EC3), noting a rise in ransomware attacks and corporate data theft which have become lucrative money spinners for criminals.
At the same time, terror groups like the Islamic State in Iraq and Syria successfully use the Internet to communicate and spread propaganda, and criminals usecyber tools and virtual currencies to move money while hiding their tracks.
Mr Amann was speaking at the 4th Interpol-Europol cybercrime conference at the Interpol Global Complex for Innovation (IGCI). Also speaking at the start of the three-day conference was IGCI executive director Noboru Nakatani. He said the rise in such crimes and the challenge for police to solve them - especially given their cross-border nature - meant that law enforcement agencies needed to collaborate ever more closely.
They had to do so with one another, with the private sector and institutions with the know- how, and with affected parties.
"In the law enforcement community, and sectors like banking, there is a mentality called the 'need-to-know', which was a guiding principle for a long time," he said. "But now, when it comes to information-sharing on cyberthreats - ransomware, phishing, e-mail - we need to change from 'need-to-know' to 'need-to-share'."
This is where an agency like Interpol comes in, providing a platform for its 190 member countries and their personnel to build trust and understanding leading to information-sharing. It is also where members can develop cybercrime-fighting capacities if they do not yet have such capabilities.
Mr Steven Wilson, who heads EC3, said there has already been a significant attitude change.
"At a conference two years ago, we had the banks and law enforcement at opposite ends of the stage, pointing fingers at each other and saying the other was at fault," he recalled.
"But at the same conference last year, we had five case studies from European countries of banks and law enforcement working together to huge success. That's a huge change... When people see the benefits, more and more they'll want to cooperate."