How To Fix CVE-2021-34991- A Pre-Authentication Buffer Overflow On Multiple Netgear Products?

Researchers identified a pre-authentication buffer overflow vulnerability (CVE-2021-34991) that affects multiple Small Offices/Home Offices (SOHO) Netgear router modules. The vulnerability tracked as CVE-2021-34991 lets attackers perform remote code execution attacks on the vulnerable devices and take control of the devices from the remote. Let’s see how to fix CVE-2021-34991- A Pre-Authentication Buffer Overflow vulnerability on Multiple Netgear Products.

Summary of CVE-2021-34991:

Researchers identified a pre-authentication buffer overflow vulnerability (CVE-2021-34991) that affects multiple Small Offices/Home Offices (SOHO) Netgear router modules. The vulnerability tracked as CVE-2021-34991 lets attackers perform remote code execution attacks on the vulnerable devices and take control of the devices from the remote. Let’s see how to fix CVE-2021-34991- A Pre-Authentication Buffer Overflow vulnerability on Multiple Netgear Products.

This vulnerability is associated with the UPnP service, a service that is used by networked devices, such as personal computers, printers, Internet gateways, Wi-Fi access points, and mobile devices to discover other network devices on the same network to establish other functional network services.

UPnP service allows any device on the network to connect to the server without authentication and reconfigure the network to support its operations. This feature of UPnP provides a large attack surface for the attacker as the service allows unauthenticated HTTP SUBSCRIBE and UNSUBSCRIBE requests from clients who wish to receive updates and parse complex input to handle those requests.

The vulnerability that exists in the validation of the UUID request header comes as input. Since there is no proper validation process in the length of user-supplied data prior to copying it to a fixed-length stack-based buffer, an attacker can send more data to the local stack buffer and then validate it. This allows the attacker to perform a Pre-Authentication Buffer Overflow attack.

The disturbing part of the vulnerability is since the UPnP service runs in root privilege, the attacker can perform code executions with root privileges. You can read the original post for complete technical details.

List Of Netgear Products Vulnerable To CVE-2021-34991 Buffer Overflow Vulnerability:

As per the report, these are the Netgear products vulnerable to the buffer overflow vulnerability.

List Of Products Netgear Released Fix For The CVE-2021-34991 Vulnerability:

at the time of publishing this post, NETGEAR has released fixes for the following products:
Extenders:

Routers: