A new feature synchronization with the Google Authenticator cloud is under fire from privacy advocates who claim that communication between the endpoint and the cloud is not encrypted and can be intercepted by attackers.
The sync feature was added by Google to help users back up their two-factor authentication codes to the cloud.
Researchers at Mysk analyzed the network traffic of the updated Google Authenticator app and reported that it "turned out that the traffic is not end-to-end encrypted."
“Google just updated the 2FA Authenticator app and added a much-needed feature: the ability to sync between devices. TL;DR: Don't enable it”, Mysk explained in a tweet. "While syncing 2FA codes across devices is convenient, it comes at the expense of your privacy."
The researchers said that with the lack of encryption, it is very likely that we will see data leaks and attacks on Google accounts. A successful attack will give the attacker access to the two-factor authentication QR code used to generate one-time codes.
“Each 2FA QR code contains a seed, which is used to generate the one-time codes. If someone knows the seed, they can generate the same one-time passwords and bypass 2FA protections. So if there is ever a data breach or if someone gains access to your Google account, all 2FA seeds will be compromised.”
Paul Ducklin on the Naked Security blog of Sophos said that anyone who can Google your data will be able to access sensitive authentication data.
Mysk researchers recommend that users who are concerned about privacy disable the new sync feature in the Google Authenticator app.
A tweet from Christian Brand of Google, an identity and security product manager, said it recognizes privacy concerns and said Google plans to provide end-to-end encryption for the app.