Citizen Lab said in its report that it had been able to identify a handful of civil society victims whose iPhones had been hacked using surveillance software developed by the Israeli company, QuaDream Ltd - a lower-profile competitor to the Israeli spyware company NSO Group. In its report published at the same time, Microsoft said it believed with "high confidence" that the spyware was "strongly linked to QuaDream."

In a statement, Microsoft Associate General Counsel Amy Hogan-Burney said that mercenary hacking groups like QuaDream "thrive in the shadows" and that publicly outing them was "essential to stopping this activity."

Israeli lawyer Vibeke Dank, whose email was listed on QuaDream's corporate registration form, did not return a message seeking comment. Repeated attempts by Reuters to reach QuaDream over the past year - including a visit to the company's office outside Tel Aviv - have been unsuccessful.

Reuters reported in 2022 that QuaDream had previously developed a no-interaction-needed hacking tool similar to the programs deployed by NSO. Such hacking tools, known as "zero-click," are particularly prized by cybercriminals, spies, and law enforcement because they can remotely compromise devices without an owner needing to open a malicious link or download a tainted attachment.

(Reporting by Raphael Satter; Editing by Anna Driver)

By Christopher Bing and Raphael Satter