Google is offering free replacements for Bluetooth-enabled Titan Security Keys following the discovery of a misconfiguration in its pairing protocols that could potentially give attackers access to user accounts under (very) precise circumstances, the company announced this week.
The Titan Security Key, a two-factor authentication device built to FIDO standards, was made available to Google Cloud customers in July 2018. This particular issue affects the Bluetooth Low Energy (BLE) version available in the US. Non-Bluetooth keys (those using NFC or USB) are not affected. Google outlines two cases in which this vulnerability can put users at risk if an attacker is within approximately 30 feet from their targets at the moment they use their keys.
When a user signs into an account, that person is prompted to active the security key by pressing a button. If an attacker is nearby and has exact timing, they could connect their own device to the target's affected security key before the target's device connects. If the attacker has the target's username and password, they could use their device to log into the target's accounts.
An attacker in close proximity could also take advantage of this bug by disguising their device as a target's vulnerable security key, and connecting to their device when they're asked to press the button during the pairing process. If successful, the attacker could change their device to appear as a Bluetooth device and potentially take actions on a target's machine, writes Christiaan Brand, product manager for Google Cloud, in a blog post on the Bluetooth bug.
Given the exact timing and information required for these scenarios to play out, most users will likely not be affected. As Brand notes, the bug doesn't interfere with the key's primary purpose, which is blocking phishing attempts from remote attackers. In the post, he offers workarounds for iOS and Android users to stay secure while using their keys and awaiting replacements.
"It is much safer to use the affected key instead of no key at all," he writes. "Security keys are the strongest protection against phishing currently available."
Still, it's worth noting that a knowledgeable, dogged attacker could pull this off. The Titan Security Keys are now available to everyone but especially common among high-profile figures, journalists, activists, and others at risk and looking for added security. As The Verge points out, their expectations for greater protection put more scrutiny on tech from providers like Google.
To check if your Titan Security Key is affected and eligible for a free replacement, look for a "T1" or "T2" on the back of the key, above the USB port. If you see one of those two, you'll likely want a new key. You can also check your Google account for affected security keys here.
Microsoft first discovered this vulnerability and shared it with companies involved in making the affected products. This meant Google, of course, along with Feitian, which produces the keys' hardware and also sells security keys under its own brand. Feitian is offering free replacements for versions 1 to 3 of its MultiPass FIDO security key, it says in an advisory.
Closing the Bluetooth Security Gaps
Google's decision to launch a BLE security key was met with criticism from other companies. One was Yubico, which had started work on a BLE security key and contributed to BLE U2F standards work, but ultimately decided not to launch the product because "it does not meet our standards for security, usability, and durability," company officials wrote in a blog post.
BLE is "much more secure than the classic Bluetooth," says Nadir Izrael, co-founder and CTO at Armis. For a security key like Titan, it makes more sense to use BLE than classic Bluetooth due to its low energy – beneficial for a longer battery life – and low bandwidth requirements.
Still, he adds, BLE is vulnerable to different kinds of attacks. With NFC and USB, it's "almost impossible" to become a "man-in-the-middle" of their communications, Izrael continues. The true appeal for using any wireless protocol, BLE included, is convenience. "The ease of connectivity offered by BLE is a compelling reason to use it in security keys," he explains.
The primary concern with any wireless protocol is exchanging security keys in a secure way. BLE is no different, and while it offers secure ways to answer this question, the security of the pairing process depends on how it's used. Companies looking to use Bluetooth or BLE in their products should take extra steps to review them carefully, he says. With the nature of connected devices, protecting against man-in-the-middle attacks should be paramount.
Google continues to push physical security keys for two-step verification. Most recently, it gave Android smartphones running version 7.0 or later the ability to be used as physical security keys for authenticating into personal Google accounts and G Suite, Google Cloud Platform, and other Google apps. The Bluetooth vulnerability disclosed this week does not affect this capability.
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