HACKERS installed spy software on phones using a major WhatsApp flaw just by calling them, it was revealed last night.

Even if the call was not picked up, the software would be installed.

2 WhatsApp has called on its 1.5billion global users to update their app after discovering hackers had accessed some users' devices and installed surveillance software just by calling them Credit: Alamy

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It gave hackers full access to phones remotely, allowing them to read messages, see contacts and switch on the camera.

The Facebook-owned messaging app is urging all its 1.5billion users to update their apps to protect themselves from further attacks.

It said the hacks targeted specific users and were carried out by "an advanced cyber actor" using software developed by Israeli cyber arms dealer NSO Group, according to the Financial Times.

The software was installed on targets' devices using the WhatsApp voice calling function.

Even if the call was not picked up, the software would be installed and the call would even be deleted from the device's call log.

WhatsApp's security team spotted the flaw and rolled out a fix on Friday.

2 It is not clear how many devices were affected, but WhatsApp said the attack was 'highly targeted' Credit: Alamy

'UPDATE' WARNING

Only a "select number" of users were targeted although the exact number is not yet known, WhatsApp said.

Human rights groups, some security companies and the US Department of Justice were informed of the glitch earlier this month, WhatsApp told the BBC.

In a statement, the firm 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."

ACCESSES CAMERA

NSO Group's flagship Pegasus software can collect intimate data from a target device.

It can even access a device's microphone and camera as well as gather location info.

In a statement, the group said: "NSO's technology is licensed to authorised government agencies for the sole purpose of fighting crime and terror.

"The company does not operate the system, and after a rigorous licensing and vetting process, intelligence and law enforcement determine how to use the technology to support their public safety missions.

"We investigate any credible allegations of misuse and if necessary, we take action, including shutting down the system.

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"Under no circumstances would NSO be involved in the operating or identifying of targets of its technology, which is solely operated by intelligence and law enforcement agencies.

"NSO would not or could not use its technology in its own right to target any person or organisation."

Danna Ingleton from Human rights group Amnesty International said: "There needs to be some accountability for this - it can't just continue to be a wild west, secretive industry."

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