Heads up Netgear router users! An unpatched flaw has made around 79 different Netgear router models vulnerable to remote attacks. For now, no patch is available.
Unpatched Netgear Router Flaw
Reportedly, two different security researchers have found the same vulnerability affecting numerous Netgear routers. Specifically, this unpatched flaw affects 79 different Netgear router models, hence potentially risking numerous users.
Both the researchers separately found the vulnerability at different timings and have now disclosed the details.
According to one of these researchers with alias d4rkn3ss from VNPT ISC, he found the bug back in January 2020. As explained in a ZDI advisory, the bug within the HTTPD service that made it possible for an adversary to access the target router with no authentication.
The specific flaw exists within the httpd service, which listens on TCP port 80 by default. The issue results from the lack of proper validation of the length of user-supplied data prior to copying it to a fixed-length, stack-based buffer. An attacker can leverage this vulnerability to execute code in the context of root.
Following this discovery, the researcher reached out to the vendors immediately. However, the vendors couldn’t come up with a fix despite reaching the end of the disclosure period. Hence, the researcher published the advisory disclosing the bug as zero-day.
Whereas, the other researcher, Adam Nichols from cybersecurity firm GRIMM also independently discovered the same bug in May 2020. They also reported the matter independently to the vendors.
However, following the disclosure of the bug in ZDI’s advisory, Nichols also published a detailed blog post sharing the technicalities of the exploit.
Moreover, he also shared the PoC exploit on GitHub, as well as the list of all vulnerable routers. Netgear users may click here to view the complete list of devices with their firmware versions.
Potential Mitigation
According to the researcher d4rkn3ss, the only possible mitigation to avoid any exploit remains restricting device access to legit users.
Only the clients and servers that have a legitimate procedural relationship with the service should be permitted to communicate with it. This could be accomplished… most notably with firewall rules/whitelisting.
For now, no patch is available to address this vulnerability. Though Netgear may release a fix for it soon, presently, the users of Netgear routers need to remain very careful.
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