iPhones vulnerable to hacking tool for months, researchers say

Analysis: NSO Group's Pegasus spyware could allegedly track locations and access passwords

• Dozens of Al Jazeera journalists allegedly hacked using Israeli firm's spyware

For almost a year, spyware sold by Israel's NSO Group was allegedly armed with a computer security super-weapon: a zero-footprint, zero-click, zero-day exploit that used a vulnerability in iMessage to seize control of an iPhone at the push of a button.

That means it would have left no visible trace of being placed on target's phones, could be installed by simply sending a message that the victim didn't even need to click on, and worked even on phones that were running the then-latest version of iOS, the operating system for iPhones.