Enlarge (credit: Apple )

Three dozen journalists had their iPhones hacked in July and August using what at the time was an iMessage zeroday exploit that didn’t require the victims to take any action to be infected, researchers said.

The exploit and the payload it installed were developed and sold by NSO Group, according to a report published Sunday by Citizen Lab, a group at the University of Toronto that researches and exposes hacks on dissidents and journalists. NSO is a maker of offensive hacking tools that has come under fire over the past few years for selling its products to groups and governments with poor human rights records. NSO has disputed some of the conclusions in the Citizen Lab report.

The attacks infected the targets’ phones with Pegasus, an NSO-made implant for both iOS and Android that has a full range of capabilities, including recording both ambient audio and phone conversations, taking pictures, and accessing passwords and stored credentials. The hacks exploited a critical vulnerability in the iMessage app that Apple researchers weren’t aware of at the time. Apple has since fixed the bug with the rollout of iOS 14.