The malware, named Regin, is likely to have been created by computer experts working for a "nation state", according to a new report by American security company Symantec.
"In the world of malware threats, only a few rare examples can truly be considered ground-breaking and almost peerless. What we have seen in Regin is just such a class of malware," the report said.
"Its capabilities and the level of resources behind Regin indicate that it is one of the main cyber-espionage tools used by a nation state," the report added.
The Symantec's report did not say which government might be behind Regin.
The report suggests that Regin is comparable in complexity to the Stuxnet virus, 'The Times' reported.
Stuxnet virus ultimately destroyed uranium centrifuges that were central to the Iranian nuclear programme. The US and Israeli governments were said to be behind the attack, although neither admitted to it.
Regin infections occurred between 2008 and 2011, after which the malware disappeared before a new version surfaced in 2013.
The victims were tricked into visiting fake websites, from which the virus was installed on to their computer.
Russia accounted for most infections, at 28 per cent, followed by Saudi Arabia, at 24 per cent. Ireland and Mexico each accounted for about 10 per cent of infections.
Iran, Afghanistan, India, Belgium, Austria and Pakistan were also affected by the virus.
Many components of Regin remain undiscovered and additional versions may exist, the report warned.