OActive claims that a password leak allows others to remotely control WeMo devices, perform malicious firmware updates, and access an internal home network.
The Belkin WeMo firmware images that are used to update the devices are signed with public key encryption to protect against unauthorised 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.
Belkin claims that they are aware of the research Companies finding but at this stage no fix is currently available.
The research Company said that 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.
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. Also, 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.
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 victims network the device can be used as a foothold to attack other devices such as laptops, mobile phones, and attached network file storage.
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