A researcher has discovered what he describes as a "backdoor" in DSL routers that could enable attackers to gain administrative access.

In a post on the GitHub site, researcher Eloi Vanderbeken offers a proof of concept showing how he was able to crack his own Linksys DSL router and gain administrative access to a home network without authentication. Subsequent posts indicate that the proof of concept would also work on routers made by other vendors.

The backdoor was found through scans of a little-known port, 32764/TCP, which is now being scanned more broadly, according to the Internet Storm Center (ISC).

"We do see a lot of probes for port 32764/TCP," says ISC's Johannes Ullrich in an online post. "At this point, I urge everybody to scan their networks for devices listening on port 32764/TCP. If you use a Linksys router, try to scan its public IP address from outside your network.

"Our data shows almost no scans to the port prior to today, but a large number from 3 source IPs [on Jan. 2]," ISC's post says.

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