Cyber security firm Symantec says it's just discovered the most sophisticated piece of malware - that's malicious software - it's ever seen.
The company, which has dubbed it "Regin", said that once it infects a computer, it can take screenshots, steal passwords and even recover deleted files. That makes it even more sophisticated than Stuxnet, a bug developed by the US and Israeli government in 2010 to target Iran's nuclear programme.
Although Symantec shied away from suggesting where it had been developed, it hinted that a "western government" may have created it, and added that most of its victims have been in Russia, Saudi Arabia and Ireland.
It is likely that its development took months, if not years, to complete and its authors have gone to great lengths to cover its tracks. Its capabilities and the level of resources behind Regin indicate that it is one of the main cyberespionage tools used by a nation state.
The company also suggested that it's been in circulation for six years, which it said "highlights how significant investments continue to be made into the development of tools for use in intelligence gathering".
Stephen Bonner, a partner in KPMG's cyber security practice, said it carried the "fingerprints of a sophisticated cyber espionage operation".
Over time we are discovering more and more about the scale of these operations, as well as the growing variety of corporate information which seems to be targeted for espionage – in this case including hospitality and airline targets, as well as telecommunication backbones.