The light given off by some WiFi light bulbs may expose more than just a dark room as Check Point researchers have found a vulnerability in Philips Hue smart bulbs and bridge enabling them to remotely infiltrate the device.
The specific vulnerability is CVE-2020-6007 a Heap-based Buffer Overflow that occurs when handling a long ZCL string during the commissioning phase, resulting in a remote code execution. Check Point’ Institute for Information Security team was able to take control of a light bulb and install malware enabling them to take over the device’s control bridge and attack the network.
The overall process to abuse the vulnerability is a bit convoluted and requires some action on the part of the homeowner.
According to Check Point:
- The hacker 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 will 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.
The bulb’s manufacturer Philips and Signify were notified and have pushed out a firmware patch.