Apple and Amazon, two of the largest makers of connected devices, now have operational low-power communications networks that piggyback on their devices to power a variety of services. But security experts are scrutinizing whether the transfer of simple messages expands their devices' attack surface.
Last week, Amazon announced that its Sidewalk connected-device network became active. Originally announced in 2019, the network uses the bandwidth of Amazon gateway devices, such as Ring cameras, or Bluetooth Low Energy (BLE) devices. For its part, Apple announced its AirTag tracking devices in May, which use its Find My network that sends messages by utilizing bandwidth of nearby Apple devices.
The networks — and the parasitic bandwidth-sharing — raise questions about how easily such technology could be abused, says Johannes Ullrich, dean of research for SANS Technology Institute. Hackers will find ways to send data over the network, even though Amazon is limiting the total bandwidth for a particular gateway to 80 Kbps.
"It's about sharing data and bandwidth — random people are able to use your device, but you are also able to use their device," he says. "As far as risks go, you don't know who actually uses your device or what they are using it for. You have no control over who is using your device or how they are using it."
Concerns over the two device makers' pervasive networks underscore that security will be a major part of the future considerations for the technology. While Apple has operated its Find My network for years, the recent addition of the AirTags connected trackers has renewed scrutiny. Apple's Find My network has already been co-opted to send attacker-crafted messages and as a covert channel for sending data. Although user data has not been compromised, the company has discussed some of its defenses to make the network privacy-friendly and recently announced it will open up the Find My network to approved partners. Amazon has promised the same with its Sidewalk network.
In many ways, especially for the user whose device is sending data, the risks are no greater than when they are sending data using an Internet service provider, Ullrich says.
"Once your data leaves your device, you have no control over how it is routed across the Internet," he says. "And sharing networks, everything is encrypted by default. There is no unencrypted option for these networks."
Risks, however, do exist.
To prevent denial-of-service attacks, communications traffic may be parsed to verify that it is valid traffic. Any time a device peers at data input from an untrusted user, security could be attacked, says SANS's Ullrich.
"You are basically accepting these messages from random users, and the question is, how good is the implementation?" he says. "Amazon Sidewalk has to parse the message and make sure it is a valid message, so there could be code execution attacks if a vulnerability is found."
In a brief analysis posted to the SANS blog, Ullrich recommends that users opt out of Amazon Sidewalk until security researchers have had a reasonable time to look at the company's implementation.
Amazon has published a security whitepaper outlining the steps the company has taken to secure its technology, including three layers of encryption and trusted identities for devices.
"As a crowdsourced, community benefit, Amazon Sidewalk is only as powerful as the trust our customers place in us to safeguard customer data," the company stated. "To that end, this document outlines the steps we have taken to secure the network and maintain customer privacy."
Apple has also committed to the privacy of its users and says its Find My network is totally anonymous.
Despite the due diligence that Amazon and Apple have conducted, consumers would be better served if the specifications for the companies' pervasive networks were opened up to the community, says SANS's Ullrich. At this point, the Amazon documentation is vague, with few details on how the protocol really works, he says.
"It is really asking for a standard," he says. "Why do we need to have multiple networks? The whole open source idea, where I can inspect the actual protocols or software, I can potentially find flaws but also improve on the protocol. Over time, as more developers gain access, hopefully, they will open up that documentation."