A year after it was first discovered, a backdoor in industrial networking kit from Canadian RuggedCom is to be fixed – sometime soon.
The company, a Siemens subsidiary via acquisition in March, has announced that it will release new firmware disabling backdoor access to devices running its ROS operating systems. These include Ethernet switches and serial-to-Ethernet converters.
The vulnerability was made public by Justin W Clarke on the Full Disclosure list, including his claim to have notified the vendor last year and, after an eight-month hiatus, notifying US-CERT in February.
RuggedCom says all versions of its firmware prior to ROS v3.3 can be backdoored via the serial console, ssh, https, telnet and rsh; later versions can’t be attacked via ssh or https, but are still vulnerable via telnet or rsh if these services are switched on (they’re enabled by default, but can be switched off in ROS v3.3 or later).
The vulnerability was created by what seems to be a clumsy attempt to allow access to devices if the customer loses a password. The undocumented “factory” account generates a password based on a hash of the device’s MAC address.
However, with both a default account and a default state that made remote access available, devices were vulnerable to anybody that knew the secret. When the new firmware version ships, the factory account will be removed, and telnet and rsh will be disabled by default. ®