Easter egg: DSL router patch merely hides backdoor instead of closing it

The same security researcher who originally discovered a backdoor in 24 models of wireless DSL routers has found that a patch intended to fix that problem doesn’t actually get rid of the backdoor—it just conceals it. And the nature of the “fix” suggests that the backdoor, which is part of the firmware for wireless DSL routers based on technology from the Taiwanese manufacturer Sercomm, was an intentional feature to begin with.

Once the backdoor is switched back on, it listens for TCP/IP traffic just as the original firmware did, giving “root shell” access—allowing anyone to send commands to the router, including getting a “dump” of its entire configuration.