Security Researchers Sound Alarm on Smart Doorbells

Consumers looking to purchase video doorbells this holiday season would do well to stick with reputable and trusted brands.

A recent review of nearly a dozen inexpensive video doorbells sold via online markets such as Amazon and eBay uncovered multiple security vulnerabilities in each device. The most serious among them was the practice by some of the devices to send Wi-Fi names, passwords, location information, photos, video, email, and other data back to the manufacturer for no obvious reason.

Security consultancy the NCC Group, in collaboration with UK consumer organization Which?, selected 11 video doorbells available on popular online markets in the UK. Some looked very similar to each other but were from different manufacturers. Other devices looked like copycats of Amazon Ring. All of the products had prices that were substantially lower than the average retail price for well-known brands, such as Ring and Google's Nest Hello smart doorbell.

Though most of the tested models were from little-known brands, some of them had high user ratings and one of the products even was endorsed with Amazon's Choice logo — meaning the retailer had recommended the product.

The NCC Group and Which? study uncovered security issues related to the hardware, associated applications, and servers that streamed and transferred data from the doorbells.

For example, two video doorbells from Victure and Ctroncs had a security flaw in them that could allow an attacker to steal the network password and use it to hack into the doorbell and the router as well as other devices connected to the network.

Another smart doorbell from Victure, which Amazon had labeled as a top seller and had a score of 4.3 out of 5 stars from over 1,000 users, was found to be sending a lot of sensitive data, including the Wi-Fi network name and password, in unencrypted fashion to servers in China.

One device being sold on Amazon and eBay, which had no discernible brand associated with it, had a vulnerable WPA-2 protocol implementation that would allow an attacker to gain access to a video doorbell owner's entire home network. A Qihoo 360 smart video door, on Amazon, was easy to hack with just a standard SIM-card ejector, and another had a flaw that allowed attackers to knock the device offline by setting the device back to a "pairing" stage.

Phoning Home
"Given their availability across various online marketplaces, but very little information about the devices and their security, we felt it would be interesting to test them from a secure design and implementation perspective," says Matt Lewis, research director at NCC Group.

"The most surprising finding was seeing some of the doorbells sending home Wi-Fi passwords over the Internet and unencrypted to remote servers," he says. "It's not really clear what the purpose of such a feature would be for, and it certainly exposes a person's entire home network to potential attackers and criminals."

Lewis says nearly all of the doorbells were observed sending at least some data back to remote servers located outside the UK and Europe, but it wasn't always sensitive data.

According to the NCC Group, all 11 devices that were tested had one or more high-risk security vulnerability in them and a "large number" had weak, easy-to-guess default passwords. The vendor described two of the products as being critically vulnerable and nine others as having "high impact" security issues.

"The main takeaway for consumers is to really do their homework before purchasing devices like these and, where possible, stick with popular and known brands," Lewis says. While lesser-known brands can be much cheaper, they usually have missing or inadequate security design and features, he says.

The new report highlights what numerous researchers have described as the growing threat to Internet security from insecure Internet of Things (IoT) devices. They have noted how a large percentage of smart devices — doorbells, connected thermostats, TVs, routers, printers, etc. — being installed in homes around the world are very weakly protected against snooping, data theft, sabotage, and other attacks.

The Mirai distributed denial-of-service (DDoS) attacks of 2016 were the first to demonstrate how attackers could abuse insecure IoT devices to cause widespread havoc. Since then, there have been numerous other incidents where attackers have hijacked large numbers of IoT devices and assembled botnets for launching DDoS attacks and for distributing ransomware and other malware.

Concerns over IoT vulnerabilities have prompted some legislative action. One example is California's Internet of Things Security Law, which went into effect January 2020. The law requires manufacturers of connected devices to implement reasonable measures to protect any information that the devices might collect, contain, or transmit.