As Iran met in Kazakhstan this week with members of the UN Security Council to discuss its nuclear program, researchers announced that a new variant of the sophisticated cyberweapon known as Stuxnet had been found, which predates other known versions of the malicious code that were reportedly unleashed by the U.S. and Israel several years ago in an attempt to sabotage Iran’s nuclear program.

The new variant was designed for a different kind of attack against centrifuges used in Iran’s uranium enrichment program than later versions that were released, according to Symantec, the U.S-based computer security firm that reverse-engineered Stuxnet in 2010 and also found the latest variant.

The new variant appears to have been released in 2007, two years earlier than other variants of the code were released, indicating that Stuxnet was active much earlier than previously known. A command-and-control server used with the malware was registered even earlier than this, on Nov. 3, 2005.