New Delhi: Indian cyber security agency, the Indian computer emergency response team (CERT-In) has flagged a vulnerability in the WhatsApp "device-linking" feature that enables attackers to take "complete" control of an account, including access to real-time messages, photos, and videos on the web version.

‘GhostPairing’ campaign explained

The agency named the issue "GhostPairing" on Friday in an advisory that has been accessed by PTI.

"It has been reported that malicious actors are exploiting WhatsApp's device-linking feature to hijack accounts using pairing codes without authentication requirement.

"This newly identified cyber campaign called GhostPairing enable cyber criminals to take complete control of WhatsApp accounts without needing password or SIM swaps," the advisory said.

A response from WhatsApp to the revelation is awaited.

CERT-In is the national technology arm to combat cyber attacks and guarding of the Indian Internet space.

How the attack begins

The advisory said that the "high" severity attack campaign usually begins with the victim receiving a message like "Hi, check this photo" from a "trusted" contact.

The message contains a link with a Facebook-style preview. The link leads to a "fake" Facebook viewer that prompts users to "verify" to see the content. Here, the attackers exploit WhatsApp's "link device via phone number" feature by tricking unsuspecting users into entering their phone numbers, the advisory said.

This way, the victims "unknowingly" grant the attackers full access to their WhatsApp accounts.

What attackers can do after linking

The 'GhostPairing' attack tricks users into granting an attacker's browser access, as an additional trusted and hidden device, by using a pairing code that looks authentic.

The advisory said that once the attacker links their device, they get almost the same access as the victim would get on WhatsApp web.

They can read messages that sync to their device, receive new messages in real-time, view photos, videos and voice notes, and they can send messages to the victim's contacts and group chats, the advisory said.

Safety measures advised

The agency suggested such counter-measures as not clicking suspicious links even if they come from known contacts and not entering one's phone number on external sites claiming to be WhatsApp or Facebook.

PTI