Home Automation Devices Open to Attack

Tuesday, February 18, 2014 @ 01:02 PM gHale


The Internet of Things remains a viable tool with incredible potential for the future, but it needs serious players to think about some serious security because, if not, the potential could lead to dire consequences.

Take one small example like the Belkin WeMo Home Automation devices. Researchers found multiple vulnerabilities in the devices that could affect over half a million users. Belkin’s WeMo uses Wi-Fi and the mobile Internet to control home electronics anywhere in the world directly from the users’ smartphone.

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The multiple vulnerabilities, found by Mike Davis, IOActive’s principal research scientist, set that gives attackers the ability to:
• Remotely control WeMo Home Automation attached devices over the Internet
• Perform malicious firmware updates
• Remotely monitor the devices (in some cases)
• Access an internal home network

“As we connect our homes to the Internet, it is increasingly important for Internet-of-Things device vendors to ensure that reasonable security methodologies are adopted early in product development cycles,” Davis said.

The vulnerabilities found within the Belkin WeMo devices expose users to several potentially costly threats, from home fires with possible tragic consequences down to the simple waste of electricity. The reason for this is, after attackers compromise the WeMo devices, they can end up used to remotely turn attached devices on and off at any time. Given the number of WeMo devices in use, it is likely that many of the attached appliances and devices will be unattended, thus increasing the threat posed by these vulnerabilities.

Additionally, once an attacker has established a connection to a WeMo device within a victim’s network; the device can act as a foothold to attack other devices such as laptops, mobile phones, and attached network file storage.

The Belkin WeMo firmware images used to update the devices end up signed with public key encryption to protect against unauthorized modifications. However, the signing key and password leak on the firmware already installed on the devices. This allows attackers to use the same signing key and password to sign their own malicious firmware and bypass security checks during the firmware update process.

Belkin WeMo devices also do not validate Secure Socket Layer (SSL) certificates preventing them from validating communications with Belkin’s cloud service including the firmware update RSS feed. 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 pushes to the victim’s home regardless of which paired device receives the update notification or its physical location.

The Internet communication infrastructure used to communicate Belkin WeMo devices is from a protocol designed for use by Voice over Internet Protocol (VoIP) services to bypass firewall or NAT restrictions. It does this in a way that compromises all WeMo devices security by creating a virtual WeMo darknet where all WeMo devices can connect directly; and, with some limited guessing of a ‘secret number,’ controlled even without the firmware update attack.

The Belkin WeMo server application programming interface (API) was also vulnerable to an XML inclusion vulnerability, which would allow attackers to compromise all WeMo devices.

IOActive worked closely with CERT on the vulnerabilities discovered. CERT made several attempts to contact Belkin about the issues, however, Belkin was unresponsive.

Belkin said the vulnerabilities highlighted by IOActive have already been addressed.

IOActive said it had notified Belkin of the flaws via CERT, but claimed the company was unresponsive. However, Belkin said they addressed the security holes with various updates made in the previous months.

The company is blaming “a miscommunication between various parties.”

Belkin said the XML injection vulnerability in the WeMo API server was fixed on November 5. On January 24, a firmware update was rolled out to add SSL encryption and validation, eliminate the storage of signing keys on the device, and set password protection on the serial port interface.



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