A highly sophisticated cyberspying tool has been used since 2008 to steal information from governments, businesses and others, security researchers said Monday.

The security firm Symantec said the malware, known as Regin, was seen “in systematic spying campaigns against a range of international targets,” including governments infrastructure operators, businesses, researchers and private individuals.

Symantec said the malware shares some characteristics with the Stuxnet worm– a tool believed to have been used by the US and Israeli governments to attack computer networks involved in Iran’s nuclear program.

Because of its complexity, the Symantec researchers said in a blog post that the malware “would have required a significant investment of time and resources, indicating that a nation state is responsible.”

The researchers added that “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.”

They described Regin as “a multi-staged threat,” with each stage hidden and encrypted.

Each individual stage provides little information on the package and “only by acquiring all five stages is it possible to analyze and understand the threat,” the researchers said.

– Lurking in shadows –

The researchers also said many components of Regin are still probably undiscovered and that there could be new versions of this tool which have not yet been detected.

The infections occurred between 2008 and 2011, after which the malware disappeared before a new version surfaced in 2013.

The largest number of infections discovered — 28 percent — was in Russia, and Saudi Arabia was second with 24 percent. Other countries where the malware was found included Mexico, Ireland, India, Afghanistan, Iran, Belgium, Austria and Pakistan. There were no reported infections in the United States.

Around half of all infections occurred at addresses belonging to Internet service providers, but Symantec said it believes the targets of these infections were customers of these companies rather than the companies themselves.

Telecom companies were also infected, apparently to gain access to calls being routed through their infrastructure, the report noted.

Regin appeared to allow the attackers to capture screenshots, take control of the mouse?s point-and-click functions, steal passwords, monitor traffic and recover deleted files.

Symantec said some targets may have been tricked into visiting spoofed versions of well-known websites to allow the malware to be installed, and in one case it originated from Yahoo Instant Messenger.

The news comes amid heightened concerns on cyberespionage.

Last month, separate teams of security researchers said the Russian and Chinese governments are likely behind widespread cyberespionage that has hit targets in the US and elsewhere.

One team of researchers led by the security firm Novetta Solutions said it identified a hacker group believed to act “on behalf of a Chinese government intelligence apparatus.”

A separate report by the security frim FireEye said a long-running effort to hack into US defense contractors, Eastern European governments and European security organizations is “likely sponsored by the Russian government.”