Billions Of Bluetooth Devices Vulnerable To Code Execution, MITM Attacks

Billions of Bluetooth-enabled devices -- including laptops, smartphones, TVs, smart watches, and automobile audio systems -- are vulnerable to attacks that would let intruders take control of the devices, install malware on them, and carry out other malicious activities, according to new research.

The vulnerabilities were discovered in Bluetooth implementations in Android, Windows, Linux and all iOS versions before Version 10. The flaws give attackers a way to quickly infect broad swaths of devices—including those that have been "air-gapped"—without any user interaction, IoT security vendor Armis cautioned in an advisory Tuesday.

Armis has dubbed the set of eight zero-day flaws it discovered as 'BlueBorne'. The company described the flaws as more severe than previously-discovered security issues in the Bluetooth protocol because of their potential to enable remotely-executable attacks that bypass authentication mechanisms and do not require devices to be paired -- or even discoverable.

The flaws give attackers a way to infect one Bluetooth device with malware and then broadcast that malware quickly over-the-air to other nearby Bluetooth devices. Attackers can take advantage of Bluetooth's on-by-default status in most devices to drop ransomware, steal data, conduct cyber espionage, or assemble Mirai-like botnets of infected Bluetooth devices.

Google, Microsoft and have issued patches for the flaws, and security teams responsible for the various Linux distributions have been informed of the issue and are working on fixes as well, Armis said.

Bluetooth is used primarily for consumer devices. "In an ideal world, BlueBorne wouldn’t be a major concern to enterprises," says Mike Buckbee, security engineer at Varonis. But BlueBorne a problem affects a vast number of devices that employees, customers, and devices use on a daily basis -- and which are unlikely to get patched quickly, he says. Many Bluetooth systems are IoT devices that cannot be easily patched -- or for which patches are never issued.

"The concern over this vulnerability stems solely from the collective inability to rapidly deploy a fix to the millions of mobile devices that would benefit from it," Buckbee noted.

In an era of IoT and Bring Your Own Device (BYOD) policies, many enterprises assume that the operating systems and technology stacks on their users' devices are being properly secured by the device manufacturers, OS creators, and carriers. "BlueBorne highlights the challenges with that approach," Buckbee says. "Enterprises need to constantly evaluate the threat posed by devices left perpetually unpatched."

Four of the eight zero-day vulnerabilities that Armis disclosed this week affect Android. One of the flaws enables information disclosure; two enable remote code execution; the fourth lets attackers execute a man-in-the-middle attack.  

All Android devices except those that use Bluetooth Low Energy (BLE) were found to have the four vulnerabilities, and are therefore are at risk of attack if the devices remain unpatched. Examples of affected Android devices include Google Pixel, Samsung Galaxy, LG Watch Sport, and the Pumpkin car audio system installed in some Audi automobiles and other vehicles.

Armis discovered one zero-day flaw in a Bluetooth implementation for Windows. It was identical to the man-in-the-middle flaw in Android, and gives attackers a way to create a malicious network interface on the victim device, enabling it to route all communications via a malicious IP address. All Windows systems since Windows Vista are impacted by the flaw and will need to be patched, Armis said.

Two of the newly-discovered vulnerabilities could affect various Linux distributions. One was an information-leak flaw, while the other was a stack overflow issue in the Bluetooth stack of the Linux Kernel. Like the information-disclosure bugs in Android and Windows, the Bluetooth vulnerability in Linux lets attackers send specially-crafted requests to vulnerable devices and get them to disclose memory bits that can then be used to extract sensitive data from the device, Armis said. The memory corruption bug allows for total device compromise.

All Linux devices running the official Bluetooth stack (BlueZ) are vulnerable to the information leak problem, while Linux devices going back to version 3.3-rcl from 2011 have the memory corruption bug, Armis said. Examples of affected Linux devices include the Samsung Gear S3 smartwatch, Samsung Smart TVs, and Samsung refrigerators.

Current endpoint protection and mobile data management tools are typically not designed to spot Bluetooth-borne attacks, so new tools will be needed to mitigate such threats going forward, Armis said.

Lamar Bailey, director of security research and development at Tripwire, says the Blueborne vulnerabilities are a good reason why IT security teams should treat Bluetooth like any open port. "[The best] mitigation is to turn it off, unless you must have it," Bailey says. "Use wired devices when possible," especially around sensitive data, he says.

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