The notorious Stuxnet malware attack that targeted Iranian nuclear facilities was deployed by “an inside mole recruited by Dutch intelligence agents at the behest of the CIA and the Israeli intelligence agency, the Mossad,” according to a new report by Yahoo News based on information provided by anonymous sources. The malware was first uncovered by researchers in 2010, but the campaign was launched in 2007 to target the Natanz nuclear enrichment plant.

The operation started in 2004 when the CIA and Mossad asked the Dutch intelligence agency AIVD  for assistance in targeting the Natanz facility. In 2007, the AIVD recruited an Iranian engineer who initially provided US security experts with information that helped them develop a powerful exploit that could infiltrate the plant’s systems. In the next stage, the recruit also provided the inside access needed to actually deploy the malware.

Read more: Revealed: How a secret Dutch mole aided the U.S.-Israeli Stuxnet cyberattack on Iran