Security Experts:

IOActive: Belkin's WeMo Home Automation Devices Open Doors for Attackers

Security firm IOActive warned on Tuesday that it has uncovered multiple vulnerabilities in Belkin WeMo Home Automation devices that could affect over 500,000 users. 

Belkin’s WeMo uses Wi-Fi and mobile Internet to enable users to control home electronics from any location in the world from their smartphone.

According to Mike Davis, IOActive’s principal research scientist, vulnerabilities in WeMo give attackers the ability to remotely control WeMo Home Automation attached devices over the Internet, perform malicious firmware updates, and in some cases, remotely monitor the devices.

Additionally, Davis found that if an attacker successfully connects to a WeMo device within a victims' network, the device can be used to access other devices such as laptops, mobile phones, and attached network file storage on an internal home network.

Vulnerabilities“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. “This mitigates their customer’s exposure and reduces risk. Another concern is that the WeMo devices use motion sensors, which can be used by an attacker to remotely monitor occupancy within the home.”

“While the benefits of [the Internet of Things] are myriad, the reality is that it offers hackers millions of new access points to a variety of networks,” Chris Hinkley, a Senior Security Engineer at FireHost, wrote in a recent SecurityWeek column.

According to IOActive, the vulnerabilities found within WeMo devices expose users to several dangerous threats, from fires to the waste of electricity.

“The reason for this is that, after attackers compromise the WeMo devices, they can be used to remotely turn attached devices on and off at any time,” IOActive explained. “Given the number of WeMo devices in use, it is highly likely that many of the attached appliances and devices will be unattended, thus increasing the threat posed by these vulnerabilities.”

According to IOActive, the vulnerabilities include:

Unauthorized Firmware Updates - The Belkin WeMo firmware images that are used to update the devices are signed with public key encryption to protect against unauthorized modifications. However, the signing key and password are leaked on the firmware that is 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.

SSL Certificates Not Validated - Belkin WeMo devices 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 is pushed to the victim’s home regardless of which paired device receives the update notification or its physical location.

Vulnerable Communication Protocol - The Internet communication infrastructure used to communicate Belkin WeMo devices is based on an abused protocol that was 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 be connected to directly; and, with some limited guessing of a ‘secret number’, controlled even without the firmware update attack.

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

“IOActive feels very strongly about responsible disclosure and as such worked closely with CERT on the vulnerabilities that were discovered,” IOActive stated.

According to IOActive, CERT made several attempts to contact Belkin about the issues, however, Belkin was unresponsive.

In its advisory issued on Feb 18., CERT warned: "We are currently unaware of a practical solution to this problem."

Because Belkin did not issue any patches for the security gaps outlined above, IOActive issued its own advisory on Tuesday and suggests that until an update is made, customers should unplug all affected WeMo devices. 

A Belkin spokesperson responded to a SecurityWeek inquiry several hours later, saying they were looking into the vulnerability reports.

"Our security teams are looking into the vulnerabilities now," the spokesperson told SecurityWeek. "I hope to have an official statement later on this afternoon on potential fixes and timing and will update you as soon as I can."

Update: Belkin Says Security Fixes Were Already Issued for WeMo Vulnerabilities

*Updated with additional details from CERT, comment from Belkin

Subscribe to the SecurityWeek Email Briefing
view counter