Netgear has issued patches that resolve a simple bug in the firmware of 20 different router models that allow an attacker to expose the router's web panel admin password, which they can use to take over the device.
According to Trustwave security researcher Simon Kenin, the one who discovered the bug, 31 Netgear router models are affected.
Kenin found the flaw in April 2016 and had worked with Netgear for months to identify and fix all affected router models.
According to a security advisory issued by Netgear, the following router models have received firmware updates.
The hardware vendor is still in the process of issuing patches for the rest of the 11 router models, whose names have not been made public to avoid attempts from attackers to exploit and hijacked customer devices.
According to a technical blog post explaining the bug [CVE-2017-5521], an attacker can send a request to the passwordrecovered.cgi file of any Netgear router's web-based admin panel and the device will respond with the admin password in cleartext.
Kenin says that over 10,000 Netgear routers are currently connected online with their web-based administration panel exposed, but hundreds of thousands more are sitting dormant on local networks.
These routers, too, can be hijacked, if the attacker manages to launch the attack from a machine on the local network.
Last month, the US Computer Emergency Readiness Team (CERT) warned users against using Netgear R6400 and R7000 routers, which were at the time, affected by a similarly dangerous security flaw. Since then, Netgear has launched a bug bounty program to tackle security issues faster.