WhatsApp backdoor: "A huge threat to freedom of speech"

A reported 'backdoor' in WhatsApp could undermine the security of private messages

WhatsApp has a backdoor that could allow Facebook to intercept and read encrypted messages, it is claimed.

According to a report in The Guardian, the way WhatsApp has implemented its end-to-end encryption protocol makes it possible for the company to access private messages, at least in theory.

As the report explains, WhatsApp's encryption "relies on the generation of unique security keys", created using Open Whisper Systems' Signal protocol. These unique keys are traded and verified between users, to ensure that the lines of communication are secure from middlemen.

So far, so good. But it turns out WhatsApp also allegedly has the ability to automatically resend undelivered messages, forcing the generation of new encryption keys unbeknownst to the receiver (the sender is only notified, after the message has been re-sent, if the user has opted-in to encryption warnings in settings). Crucially, this re-encryption could allow WhatsApp or another party to generate known keys, which would allow them to intercept and read the message.

Advertisement - Article continues below
Advertisement - Article continues below

This setup is not native to the Signal protocol, which will fail to deliver a message if the security key has been changed while offline. Instead, the vulnerability is down to WhatsApp's implementation of the protocol, which automatically resends an undelivered message with a new key.

Tobias Boelter, a security researcher from the University of California, Berkeley, discovered the vulnerability, and reported it to WhatsApp's owner, Facebook, in 2016. He was later told that it was "expected behaviour", and The Guardian reported that it has been able to verify that the backdoor still exists.

"If WhatsApp is asked by a government agency to disclose its messaging records, it can effectively grant access due to the change in keys," Boelter told The Guardian.

A WhatsApp spokesman denied this when approached by IT Pro, saying: "WhatsApp does not give governments a 'backdoor' into its systems and would fight any government request to create a backdoor. The design decision referenced in the Guardian story prevents millions of messages from being lost, and WhatsApp offers people security notifications to alert them to potential security risks."

He added the suggestion that a government could force WhatsApp to give access was false, though The Guardian cited the Investigatory Powers Act's ability to require companies to remove "electronic protection" from data.

The backdoor was also verified by Steffen Tor Jensen, head of information security and digital counter-surveillance at the European-Bahraini Organisation for Human Rights. "WhatsApp can effectively continue flipping the security keys when devices are offline and re-sending the message, without letting users know of the change till after it has been made, providing an extremely insecure platform," he told the paper.

Advertisement - Article continues below

WhatsApp's supposed attention to information security, implementing end-to-end encryption for all messages in April last year, has made it a choice platform for dissidents, journalists and diplomats. Privacy advocates have damned this revelation of an alleged backdoor, including Professor Kirstie Ball, co-director and founder of the Centre for Research into Information, Surveillance and Privacy, who said the vulnerability was "a huge threat to freedom of speech".

"If you're using WhatsApp to avoid government surveillance, stop now," tweeted The Guardian's Samuel Gibbs.

"Having a security backdoor that forces the generation of new encryption keys is bad enough. But not making the recipient aware of this change is highly unethical," said Jacob Ginsberg, senior director at encryption software company Echoworx. "It calls into question the security, privacy and credibility of the entire service and the business.

"The fact that Facebook has known about this vulnerability since April is doubly damning. Not only could this be seen by many as supporting on-going government data collection interventions, it means their talk of encryption and privacy has been nothing more than lip service. The company needs to actively address its security measures."

WhatsApp's spokesman told IT Pro: "WhatsApp published a technical white paper on its encryption design, and has been transparent about the government requests it receives, publishing data about those requests in the Facebook Government Requests Report."

Featured Resources

What you need to know about migrating to SAP S/4HANA

Factors to assess how and when to begin migration

Download now

Your enterprise cloud solutions guide

Infrastructure designed to meet your company's IT needs for next-generation cloud applications

Download now

Testing for compliance just became easier

How you can use technology to ensure compliance in your organisation

Download now

Best practices for implementing security awareness training

How to develop a security awareness programme that will actually change behaviour

Download now


internet security

Avast and AVG extensions pulled from Chrome

19 Dec 2019

Google confirms Android cameras can be hijacked to spy on you

20 Nov 2019

Most Popular

Microsoft Windows

What to do if you're still running Windows 7

14 Jan 2020
data governance

Brexit security talks under threat after UK accused of illegally copying Schengen data

10 Jan 2020
operating systems

17 Windows 10 problems - and how to fix them

13 Jan 2020

Dell XPS 13 (New 9300) hands-on review: Chasing perfection

14 Jan 2020