Millions of routers are affected by a high severity flaw in the NetUSB module which is used by many vendors including NETGEAR, TP-Link, and Dlink.

NetUSB is developed by Kcodes and is licensed to many device manufacturers. It enables remote network devices to connect to USB peripherals which are plugged into the router – typically printers and storage devices. With the help of a driver running on the computer, the remote USB device appears to be connected directly to that computer.  Even if this feature is not being used on your network at home or in the office, the code may well be included within your router firmware.

According to a new report from Sentinelone, the NetUSB kernel module listens on TCP port 20005 on the IP 0.0.0.0 by default – in other words it is listening on both the internal LAN interface and the external WAN interface of the router.

KCodes supplied a patch to resolve this vulnerability to all their licensed vendors in November 2021, and the vulnerability was publicly disclosed by SentinelOne on 11th January 2022.

If you have routers on your network which include a remote USB connectivity feature – whether or not you are making use of it – from any of the vendors listed below you should check for a firmware update.  To mitigate the vulnerability before a patch is applied, you can add a firewall rule to block access to port 20005 from the WAN interface.

Vendors who use the NetUSB module include:

• Netgear (D7800, R6400, R6700 models)
• TP-Link
• Tenda
• EDiMAX
• DLink
• Western Digital