A couple of bugs can be chained to hack Netcomm routers

A couple of critical vulnerabilities have been discovered in Netcomm rourers, experts warn of their potential exploitation in the wild.

The vulnerabilities discovered in the Netcomm routers are a a stack based buffer overflow and an authentication bypass, respectively tracked as CVE-2022-4873 and CVE-2022-4874.

Both issues impact the Netcomm router models NF20MESH, NF20, and NL1902 running software versions earlier than R6B035.

Below are the descriptions for both issues:

CVE-2022-4873 – Authentication bypass in Netcomm router models NF20MESH, NF20, and NL1902 allows an unauthenticated user to access content. In order to serve static content, the application performs a check for the existence of specific characters in the URL (.css, .png etc). If it exists, it performs a “fake login” to give the request an active session to load the file and not redirect to the login page.

CVE-2022-4874 – Authentication bypass in Netcomm router models NF20MESH, NF20, and NL1902 allows an unauthenticated user to access content. In order to serve static content, the application performs a check for the existence of specific characters in the URL (.css, .png etc). If it exists, it performs a “fake login” to give the request an active session to load the file and not redirect to the login page.

The CERT Coordination Center (CERT/CC) also published an advisory to warn of attacks chaining the two issues to achieve remote code execution on vulnerable systems.

“Netcomm router models NF20MESH, NF20, and NL1902 running software versions earlier than R6B035 contain two vulnerabilities.” reads the advisory. “The two vulnerabilities, when chained together, permit a remote, unauthenticated attacker to execute arbitrary code.”

The advisory pointed out that once the attacker has obtained unauthorized access to affected devices, he can use those entry points to gain access to other systems on the network or compromise the availability, integrity, or confidentiality of data being transmitted from the internal network.

The flaw was discovered by Brendan Scarvell who also published PoC to show how to chain the two vulnerabilities to achieve unauthenticated remote code execution.

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Pierluigi Paganini

(SecurityAffairs – hacking, Netcomm)

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Pierluigi Paganini

Pierluigi Paganini is member of the ENISA (European Union Agency for Network and Information Security) Threat Landscape Stakeholder Group and Cyber G7 Group, he is also a Security Evangelist, Security Analyst and Freelance Writer. Editor-in-Chief at "Cyber Defense Magazine", Pierluigi is a cyber security expert with over 20 years experience in the field, he is Certified Ethical Hacker at EC Council in London. The passion for writing and a strong belief that security is founded on sharing and awareness led Pierluigi to find the security blog "Security Affairs" recently named a Top National Security Resource for US. Pierluigi is a member of the "The Hacker News" team and he is a writer for some major publications in the field such as Cyber War Zone, ICTTF, Infosec Island, Infosec Institute, The Hacker News Magazine and for many other Security magazines. Author of the Books "The Deep Dark Web" and “Digital Virtual Currency and Bitcoin”.