National Cyber Security Centre urges WhatsApp users to update their phones after a security attack

WhatsApp users should update their apps after a security attack that could have allowed hackers to spy on users’ phones, the National Cyber Security Centre has recommended.

With WhatsApp admitting that a small number of accounts have been affected and urging its 1.5 billion users to update their phones, the NCSC warned that “it’s important to apply these updates quickly, to make it as hard as possible for attackers to get in”.

WhatsApp uses end-to-end encryption, meaning messages should only be displayed in a legible form on the sender or recipient's device.

But the breach came after hackers were able to remotely install surveillance software on phones and other devices.

The surveillance software would have let an attacker read the messages on the target's device.

The company said: “The attack has all the hallmarks of a private company reportedly that works with governments to deliver spyware that takes over the functions of mobile phone operating systems.”