Owners and administrators of Linksys home routers are being advised to update and secure their devices following reports of active attacks on a flaw present in at least two models.

Researchers with the SANS Institutes Internet Storm Center have received reports of mass attacks on a remote access vulnerability in the Linksys E1000 and E1200. The reports, which were noted by an ISP administrator in Wyoming, claim that some customers running the Linksys routers have had their networks compromised.

According to the reports, the compromised routers scanned network traffic rapidly on port 80/8080, saturating available bandwidth, and in some cases their DNS settings were modified.

While the exact nature of the flaw being exploited is not yet known, early speculation is that the issue could be related to components using the home network administration protocol (HNAP).

SANS noted that E1200 routers with the latest 2.0.06 firmware version seemed to be immune to the spotted attacks, but the E1000s – which are no longer supported – were not, even with the most recent firmware installed.

Linksys did not return a request to confirm or comment on the reports.

Dr. Johannes Ullrich, chief research officer with the SANS Institute, told The Reg that in addition to updating firmware, owners and administrators of the vulnerable routers should look to tighten their administrator access controls.

"They should either turn off remote admin functionality, or restrict it to IP addresses from which they need to access the router if they can," Ullrich said.

The report comes not long after word surfaced of other security vulnerabilities found in routers made by Linksys' former parent company, Cisco. Those flaws affected a number of small business products from Cisco, and did not impact any Linksys branded devices. ®