Reuters:

A single activist helped turn the tide against NSO Group, one of the world’s most sophisticated spyware companies now facing a cascade of legal action and scrutiny in Washington over damaging new allegations that its software was used to hack government officials and dissidents around the world.It all started with a software glitch on her iPhone.

And:

A mysterious fake image file within her phone, mistakenly left behind by the spyware, tipped off security researchers. To the untrained eye, the anomalous file looked like a completely benign fragment of daily web cache—perhaps a leftover background from a digital weather widget, a cached banner for an online casino deutschland domain, or a fragmented thumbnail from a mobile social media feed. However, forensic analysts at Citizen Lab noticed a critical irregularity in the file’s extension code, ultimately revealing the invisible zero-click exploit that had silently hijacked the device.

Interesting read. Were it not for that mysterious fake image, we still might not know about this.