Vulnerabilities that would enable a hacker to deliver ransomware or other malware to business and home networks by taking over smart light bulbs and their controller have been discovered.

Researchers at cybersecurity specialist Check Point have shown how a threat actor could exploit an IoT network (smart light bulbs and their control bridge) to launch attacks on conventional computer networks in homes, businesses or even smart cities.

The researchers focused on the popular Philips Hue smart bulbs and bridge, and found vulnerabilities (CVE-2020-6007) that enabled them to infiltrate networks using a remote exploit in the ZigBee low-power wireless protocol that is used to control a wide range of IoT devices.

In an analysis of the security of ZigBee-controlled smart light bulbs published in 2017, researchers were able to take control of a Hue light bulb on a network, install malicious firmware on it and propagate to other adjacent light bulb networks. While the vendor was able to fix the propagation vulnerability, attackers could still take over a target’s Hue light bulb. Using this remaining vulnerability, Check Point researchers took this work one step further and used the Hue light bulb as a platform to take over the bulbs’ control bridge and ultimately, attacking the target’s computer network.

The attack scenario is as follows:

The hacker remotely controls the bulb’s color or brightness to trick users into thinking the bulb has a glitch. The bulb appears as ‘Unreachable’ in the user’s control app, so they try to ‘reset’ it. The only way to reset the bulb is to delete it from the app, and then instruct the control bridge to re-discover the bulb. The bridge discovers the compromised bulb, and the user adds it back onto their network. The hacker-controlled bulb with updated firmware then uses the ZigBee protocol vulnerabilities to trigger a heap-based buffer overflow on the control bridge, by sending a large amount of data to it. This data also enables the hacker to install malware on the bridge – which is in turn connected to the target business or home network. The malware connects back to the hacker and using a known exploit (such as EternalBlue ), they can infiltrate the target IP network from the bridge to spread ransomware or spyware.

Yaniv Balmas, head of cyber research, Check Point, said: “Many of us are aware that IoT devices can pose a security risk, but this research shows how even the most mundane, seemingly ‘dumb’ devices such as light bulbs can be exploited by hackers and used to take over networks, or plant malware.

“It’s critical that organizations and individuals protect themselves against these possible attacks by updating their devices with the latest patches and separating them from other machines on their networks, to limit the possible spread of malware. In today’s complex fifth-generation attack landscape, we cannot afford to overlook the security of anything that is connected to our networks.”

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George Yianni, Head of Technology, Philips Hue, said: “We are committed to protecting our users’ privacy and do everything to make our products safe. We are thankful for responsible disclosure and collaboration from Check Point, it has allowed us to develop and deploy the necessary patches to avoid any consumers being put at risk.”

The research, which was conducted with the help of the Check Point Institute for Information Security (CPIIS) in Tel Aviv University, was disclosed to Philips and Signify (owner of the Philips Hue brand) in November 2019. Signify confirmed the existence of the vulnerability in their product, and issued a patched firmware update (Firmware 1935144040) which is now available on their site. We recommend users to make sure that their product received the automatic update of this firmware version.

The full technical research details will be published at a later date, to give users time to successfully patch their vulnerable devices.

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