NETGEAR Products Vulnerability Allow for Arbitrary Code Execution

A vulnerability has been discovered in multiple NETGEAR products, which could allow for arbitrary code execution. Successful exploitation of this vulnerability could allow for arbitrary code execution in the context of the root user. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights.

THREAT INTELLIGENCE: GRIMM researchers are reported to have an exploit capable of compromising fully patched devices that are running the default configuration.

SYSTEMS AFFECTED:

• NetGear AirCards prior to firmware version 1.0.0.62
• NetGear Cable Modems prior to firmware version 2.1.3.5
• NetGear DSL Modem Routers D7000v2 and D6220 prior to firmware version 1.0.0.76
• NetGear DSL Modem Routers D6400 prior to firmware version 1.0.0.108
• NetGear DSL Modem Routers D6400 prior to firmware version 1.0.0.126
• NetGear Extenders EX3700 and EX3800 prior to firmware version 1.0.0.94
• NetGear Extenders EX6120 and EX6130 prior to firmware version 1.0.0.66
• NetGear Routers See NetGear release under references for full list of patched firmware versions.

RISK:
Government:

• Large and medium government entities: High
• Small government entities: Medium

Businesses:

• Large and medium business entities: High
• Small business entities: Medium

Home users: Low

TECHNICAL SUMMARY:

A vulnerability has been discovered in multiple NETGEAR products, which could allow for arbitrary code execution.  The specific flaw exists within the UPnP service, which listens on TCP port 5000 by default. When parsing the uuid request header, the process does not properly validate the length of user-supplied data prior to copying it to a fixed-length stack-based buffer.

Successful exploitation of this vulnerability could allow for arbitrary code execution in the context of the root user. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights.

RECOMMENDATIONS:
We recommend the following actions be taken:

• Apply appropriate patches provided by NETGEAR to vulnerable systems immediately after appropriate testing.
• Apply the Principle of Least Privilege to all systems and services

REFERENCES:
NETGEAR:

https://kb.netgear.com/000064361/Security-Advisory-for-Pre-Authentication-Buffer-Overflow-on-Multiple-Products-PSV-2021-0168

GITHUB:

https://github.com/grimm-co/NotQuite0DayFriday/tree/trunk/2021.11.16-netgear-upnp

CVE:

https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-34991