Apple fixes security hole reportedly used to hack iPhone without user action

BOSTON — Apple released a critical software patch to fix a security vulnerability that researchers said could allow hackers to directly infect iPhones and other Apple devices without any user action.

Researchers at the University of Toronto’s Citizen Lab said the security issue was exploited to plant spyware on a Saudi activist’s iPhone. They said they had high confidence that the world’s most infamous hacker-for-hire firm, Israel’s NSO Group, was behind that attack.

The previously unknown vulnerability affected all major Apple devices — iPhones, Macs and Apple Watches, the researchers said. NSO Group responded with a one-sentence statement saying it will continue providing tools for fighting “terror and crime.”

It was the first time a so-called “zeroclick” exploit — one that doesn’t require users to click on suspect links or open infected files — has been caught and analyzed, the researchers said. They found the malicious code on Sept. 7 and immediately alerted Apple. The targeted activist asked to remain anonymous, they said.

“We’re not necessarily attributing this attack to the Saudi government,” said researcher Bill Marczak.

Citizen Lab previously found evidence of zero-click exploits being used to hack into the phones of al-Jazeera journalists and other targets, but hasn’t previously seen the malicious code itself.

Although security experts say that average iPhone, iPad and Mac users generally need not worry — such attacks tend to be limited to specific targets — the discovery still alarmed security professionals.

Malicious image files were transmitted to the activist’s phone via the iMessage instant-messaging app before it was hacked with NSO’s Pegasus spyware, which opens a phone to eavesdropping and remote data theft, Marczak said. It was discovered during a second examination of the phone, which forensics showed had been infected in March. He said the malicious file causes devices to crash.

In a blog post, Apple said it was issuing a security update for iPhones and iPads because a “maliciously crafted” PDF file could lead to them being hacked. It said it was aware that the issue may have been exploited and cited Citizen Lab.