Security experts have discovered a highly sophisticated computer virus in Iran and the Middle East that they believe was deployed at least five years ago to engage in state-sponsored cyber espionage.
Evidence suggests the virus, dubbed Flame, may have been built on behalf of the same nation or nations that commissioned the Stuxnet worm that attacked Iran's nuclear program in 2010.
Researchers for Russian malware detection software marker Kaspersky Lab are yet to determine whether Flame had a specific mission like Stuxnet.
It discovered Flame after a UN telecommunications agency asked it to analyse data on malicious software across the Middle East in search of the data-wiping virus reported by Iran.
The virus has since been discovered to originate from a network of some 80 servers across Asia, Europe and North America used to remotely access infected machines. Up to 5000 infected computers were found in Iran, Israel and Palestinian, as well as Sudan, Syria, Lebanon, Saudi Arabia and Egypt.
Kaspersky has declined to say who they think built it.
Iran has accused the United States and Israel of deploying Stuxnet.
Cyber security experts said the discovery provides new evidence to the public to show what experts privy to classified information have long known: that nations have been using pieces of malicious computer code as weapons to promote their security interests for several years.
"This is one of many, many campaigns that happen all the time and never make it into the public domain," said Alexander Klimburg, a cyber security expert at the Austrian Institute for International Affairs.
A cyber security agency in Iran said on its website that Flame bore a "close relation" to Stuxnet, the notorious computer worm that attacked that country's nuclear program in 2010.
Stuxnet became the first publicly known example of a cyber weapon.
Iran's National Computer Emergency Response Team also said Flame might be linked to recent cyber attacks that officials in Tehran have said were responsible for massive data losses on some Iranian computer systems.
The virus contains about 20 times as much code as Stuxnet - which caused centrifuges to fail at the Iranian enrichment facility it attacked - and about 100 times as much code as a typical virus designed to steal financial information, according to Kaspersky Lab senior researcher Roel Schouwenberg.
It uses some 20 modules built into the code that can perform several functions including gathering data files, remotely changing settings on computers, turning on PC microphones to record conversations, accessing Bluetooth communications, taking screen shots and logging instant messaging chats.
Kaspersky Lab said Flame and Stuxnet appear to infect machines by exploiting the same flaw in the Windows operating system and that both viruses employ a similar way of spreading.
But experts at Kaspersky Lab and Hungary's Laboratory of Cryptography and System Security, who have spent weeks studying Flame, said they have yet to find any evidence that it can attack infrastructure, delete data or inflict other physical damage.
Yet they said they are in the early stages of their investigations and that they may discover other purposes beyond data theft. It took researchers months to determine the key mysteries behind Stuxnet, including the purpose of modules used to attack a uranium enrichment facility at Natanz, Iran.
"Their initial research suggest that this was probably written by the authors of Stuxnet for covert intelligence collection," said John Bumgarner, a cyber warfare expert with the non-profit US Cyber Consequences Unit think tank.
Flame appears poised to go down in history as the third major cyber weapon uncovered after Stuxnet and its data-stealing cousin Duqu, named after the Star Wars villain.
Kaspersky research shows the largest number of infected machines are in Iran, followed by Israel and the Palestinian territories, then Sudan and Syria.
Countries at war?
That means the teams that built Stuxnet and Duqu might have had access to the same technology as the team that built Flame, Schouwenberg said.
He said that a nation state would have the capability to build such a sophisticated tool but declined to comment on which countries might do so.
Mystery continues around Stuxnet's creators though reports as early as January 2011 have suggested that the US and Israel constructed the virus under a joint program begun around 2004 to undermine what they say are Iran's efforts to build a bomb.
The program was reportedly originally authorised by US President George W. Bush, and then accelerated by his successor, Barack Obama.
The countries are also thought to have gained help from Microsoft to identify and exploit weaknesses in the Windows operating system that were little known or as-yet undiscovered.
The US Defense Department, CIA, the State Department, the National Security Agency, and the US Cyber Command declined to comment.
Hungarian researcher Boldizsar Bencsath, whose Laboratory of Cryptography and Systems Security first discovered Duqu, said his analysis shows that Flame may have been active for at least five years and perhaps eight years or more.
"The scary thing for me is: if this is what they were capable of five years ago, I can only think what they are developing now," Mohan Koo, managing director of British-based Dtex Systems cyber security company.
Mikko Hypponen, chief research officer for anti-virus software maker F-Secure of Finland, described Flame as the latest of high-profile viruses that show makers of anti-virus software need to improve their performance.
He has led suggestions of countries stockpiling cyber weapons, including aggressively hiring black-hat hackers through defence contractors in order to build expertise.
"Stuxnet, Duqu and Flame are all examples where we - the anti-virus industry - have dramatically failed," he said. "All of these cases were spreading undetected for extended periods of time ... Yet, anti-virus products failed to protect users against these attacks."
(Additional reporting by Jim Wolf in Washington, Daniel Fineran in Dubai and William Maclean in London; editing by Edward Tobin, Ron Popeski and Mohammad Zargham)