Netgear has released firmware updates for several of its routers to address a critical command injection vulnerability that can be exploited to remotely hijack affected devices.
Initially, only Netgear R7000, R6400 and R8000 routers were believed to be affected, but the vendor’s analysis revealed that other models are impacted as well, including R6250, R6700, R7100LG, R7300DST and R7900. Netgear is in the process of reviewing other routers that could be vulnerable.
Considering that the vulnerability is easy to exploit, Netgear has rushed to release firmware updates that plug the security hole. Beta firmware fixes are currently available for R6250, R6400, R6700, R7000, R7100LG and R7300DST routers, and patches should become available for other models in the upcoming days.
Netgear has pointed out that the beta firmware is offered as a temporary solution and it may not work for all devices as it has not been fully tested.
“We appreciate and value having security concerns brought to our attention. Netgear constantly monitors for both known and unknown threats. Being pro-active rather than re-active to emerging security issues is fundamental for product support at Netgear,” the company said.
Security experts warned that the vulnerability can be leveraged to execute arbitrary commands with root privileges by getting the user to access a specially crafted URL or via malvertising attacks. Exploitation of the flaw can result in the router getting completely compromised.
Bas van Schaik has proposed a temporary workaround that involves exploiting the flaw itself to disable the device’s web server. However, the fix makes the web admin interface unavailable and it’s only efficient until the router is rebooted.
Accessing the following URL can show if a router is vulnerable:
http://[router-IP-address]/cgi-bin/;uname$IFS-a
If the page displays anything other than an error or an empty page, the device is affected. Van Schaik’s workaround can be applied using this URL:
http://[router-IP-address]/cgi-bin/;killall$IFS’httpd’
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