India, Sept. 3 -- iPhone owners who rely on WhatsApp are being urged to update their apps after security researchers found hackers using rare zero-click exploits to target Apple devices. Several tech firms quickly moved to patch the flaws but the warning is clear: check your updates, and for a small number of targeted users, a full factory reset may be the safest option.

The discovery centers on a pair of bugs - one inside WhatsApp itself, another inside Apple's own software. Attackers chained these weaknesses together to break into iPhones and Macs and stole messages and sensitive data. What makes this case especially unsettling is that victims didn't have to click any links or even open a suspicious message. The phone could be compromi...