Hacked - like many smart things, light bulbs can be hacked too

If you were only concerned that smart home gear could expose your private information, you can add another worry to you list: smart vendors that leave holes for hackers to exploit the equipment too.

Security researchers have used weaknesses in a wi-fi connected lightbulb product to manipulate a network of bulbs and capture credentials of the wi-fi network it relies on to operate.

Researchers at UK security firm Context honed in on nascent wireless protocols used by connected lightbulbs from LIFX — which users can control from a smartphone — illustrating that security takes second place when pushing new networked products to the smart home. 

Specifically, the researchers looked at how the bulbs shared wifi network credentials between themselves over a 802.15.4 6LoWPAN-based mesh network. 

LIFX ran a popular fundraising campaign in 2012 on Kickstarter, raising 13 times more than its original target. But while the campaign raised it enough to begin delivering the smart bulbs to home consumers, the company overlooked encrypting all data in the wireless protocols it used when enrolling new bulbs on the network. The oversight allowed the researchers to craft messages to the networked bulbs, forcing them to cough up security credentials.

“Monitoring packets captured from the mesh network whilst adding new bulbs, we were able to identify the specific packets in which the WiFi network credentials were shared among the bulbs. The on-boarding process consists of the master bulb broadcasting for new bulbs on the network. A new bulb responds to the master and then requests the WiFi details to be transferred. The master bulb then broadcasts the WiFi details, encrypted, across the mesh network. The new bulb is then added to the list of available bulbs in the LIFX smart phone application,” the researchers noted.

While the wifi details were encrypted, the researchers were able to use the hardware to discover that LIFX was using an implementation of the Advanced Encryption Standard (AES), which could be used to obtain the secret key being shared between bulbs on the network.

“AES, being a symmetric encryption cipher, requires both the encrypting party and the decrypting party to have access to the same pre-shared key. In a design such as the one employed by LIFX, this immediately raises alarm bells, implying that each device is issued with a constant global key. If the pre-shared key can be obtained from one device, it can be used to decrypt messages sent from all other devices using the same key. In this case, the key could be used to decrypt encrypted messages sent from any LIFX bulb,” Context notes.

While Context could manipulate the mesh network, capture the WiFi details and decrypt the credentials, one mediating factor was its use of the 802.15.4 6LoWPAN wireless mesh network which meant that an attacker would need to be within 30 meters of a LIFX bulb to perform this attack.

Read more: Energy providers hacked through malicious software updates

Context also noted that LIFX quickly responded to its findings by issuing a firmware update that encrypted all 6LoWPAN traffic and secured the process supporting new bulbs on the network.

Follow Liam Tung on Twitter 

This article is brought to you by Enex TestLab, content directors for CSO Australia.

Tags smartphoneWi-Fi networkhackedcontextSmart homelight bulbs

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