The "Flame" virus, the most complex computer bug ever discovered, has been lurking for years inside Iranian government computers, spying on the country's officials.
In a statement posted on its website on Monday, the Iranian National Computer Emergency Response Team (CERT) said it discovered Flame after "multiple investigations" over the past few months.
The Iranian CERT team said it believes there is a "close relation" between Flame two previous cyber attacks on Iran, known as the Stuxnet and Duqu computer worms. Stuxnet is widely believed to have been launched by either the U.S. or Israel (or both countries).
This isn't traditional war. The Internet has leveled the playing field, allowing governments that would never launch military attacks on one another to target one another in cyberspace.
"In warfare, when a bomb goes off it detonates; in cyberwarfare, malware keeps going and gets proliferated," said Roger Cressey, senior vice president at security consultancy Booz Allen Hamilton, at a Bloomberg cybersecurity conference held in New York last month.
"Once a piece of malware is launched in wild, what happens to that code and its capability?" he added. "Things like Stuxnet are being reverse-engineered."