Insecure firmware handling, poor communications practises and API vulnerabilities are among a range of vulnerabilities security company IOActive has identified in Belkin's WeMo home automation systems.
In its advisory, here, IOActive says it's discovered that the systems leak a hard-coded key and password that Belkin uses to sign firmware. This makes it a cinch for an attacker to create firmware that's presented to the user as legitimate.
Even better, while WeMo uses SSL to communicate with the RSS feed Belkin uses to distribute firmware – the systems don't bother checking the SSL certificates:
“This allows attackers to use any SSL certificate to impersonate Belkin’s cloud services and push malicious firmware updates and capture credentials at the same time. Due to the cloud integration, the firmware update is pushed to the victim’s home regardless of which paired device receives the update notification or its physical location.”
The other two vulnerabilities are also pretty choice. To get past NAT, the advisory notes, WeMo uses the STUN and TURN protocols. Abuse of these by an attacker with a WeMo device – or with control of one – would let them communicate directly with other WeMo devices in what IOActive calls “a virtual darknet” of devices.
And there's a bug in the devices' internal Web server implementation. As a CERT advisory (released in response to contact from IOActive) states, “Belkin Wemo Home Automation API server contains a XML injection vulnerability. The peerAddresses API can be attacked through XML injection, which may reveal the contents of system files.”
IOActive believes there could be as many as a million WeMo devices in the market, and notes that CERT was unable to get a response from Belkin. “We are currently unaware of a practical solution to this problem”, CERT states.
As the recent Linksys worm “The Moon” has demonstrated, if a vulnerability exists, it's going to be exploited – and the increasing capability of formerly dumb devices is making them an attractive target for attackers. Why risk discovery by putting your bots on PCs, where anti-virus might discover them, when a home automation system or a router can be recruited with far less risk of discovery.
And in the case of a home automation system, remote control means attackers can control anything the system can see – whether it's the lights, motion sensors, or appliances.
The Register expects plenty more home automation systems to carry vulnerabilities that will emerge under increasing scrutiny from the security community. ®