Hacking Wi-Fi networks by exploiting a flaw in Philips Smart Light Bulbs

Check Point experts discovered a high-severity flaw in Philips Hue Smart Light Bulbs that can be exploited to gain entry into a targeted WiFi network.

Security experts from Check Point discovered a high-severity flaw (CVE-2020-6007) in Philips Hue Smart Light Bulbs that can be exploited by hackers to gain entry into a targeted WiFi network.

Lightbulbs could be remotely controlled through a mobile app or via a digital home assistant, owners could control the light in the environment and even calibrate the color of each lightbulb. Smart lightbulbs are managed over the air via WiFi protocol or ZigBee, a low bandwidth radio protocol.

Check Point experts demonstrated that it is possible to trigger the issue into Philips Hue Smart Light Bulbs over-the-air from over 100 meters away.

The CVE-2020-6007 flaw ties the way Philips implemented the Zigbee communication protocol in its smart light bulb, it could lead to a heap-based buffer overflow issue.

ZigBee is an IEEE 802.15.4-based specification for a suite of high-level communication protocols used to create personal area networks with small, low-power digital radios, such as for home automation, medical device data collection, and other low-power low-bandwidth needs, designed for small scale projects which need wireless connection.

The buffer overflow occurs in the “bridge” component that accepts remote commands sent to the bulb over Zigbee protocol from other devices such as a mobile app.

“Check Point’s researchers showed how a threat actor could exploit an IoT network (smart lightbulbs and their control bridge) to launch attacks on conventional computer networks in homes, businesses or even smart cities.” reads the report published by CheckPoint.”Our researchers focused on the market-leading 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.”

Researchers did not reveal technical details or PoC exploit for the vulnerability to allow users to patch their systems.

The researchers published is a video that shows how they have exploited the vulnerabilities in the Philips Hue bridge to compromise a target computer network and to attack the computer itself using the EternalBlue exploit.

Below the attack chain that was visible in the video PoC:

1. The attacker takes control over the smart bulb by exploiting a vulnerability in smart light bulbs in 2017.
2. The device is not more ‘reachable’ in the users’ control app, tricking users into resetting the bulb and then instructing the control bridge to re-discover the bulb.
3. The bridge discovers the hacker-controlled bulb with updated firmware, and the user adds it back onto their network.
4. The attacker exploits vulnerabilities in the ZigBee protocol to trigger a heap-based buffer overflow on the control bridge and install a malicious code on the bridge that’s connected to the targeted network.
5. The malware could move laterally and infect other systems in the target network.

“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 lightbulbs can be exploited by hackers and used to take over networks, or plant malware.” explianed Yaniv Balmas, head of cyber research at Check Point. “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.”

Check Point reported the issue to Philips and Signify (owner of the Philips Hue brand) in November 2019. The company released firmware patches for the device in January.

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Pierluigi Paganini

(SecurityAffairs – Smart Light Bulbs, hacking)

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