CVE-2023-34285 in RAX30
Summary
by MITRE • 05/03/2024
NETGEAR RAX30 cmsCli_authenticate Stack-based Buffer Overflow Remote Code Execution Vulnerability. This vulnerability allows network-adjacent attackers to execute arbitrary code on affected installations of NETGEAR RAX30 routers. Authentication is not required to exploit this vulnerability.
The specific flaw exists within a shared library used by the telnetd service, which listens on TCP port 23 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. Was ZDI-CAN-19918.
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Analysis
by VulDB Data Team • 01/03/2025
The CVE-2023-34285 vulnerability represents a critical stack-based buffer overflow flaw in NETGEAR RAX30 routers that exposes a remote code execution vector without requiring authentication. This vulnerability specifically targets the cmsCli_authenticate function within a shared library utilized by the telnetd service, which operates on the well-known TCP port 23. The flaw stems from insufficient input validation mechanisms that fail to properly check the length of user-supplied data before copying it into a fixed-length stack buffer, creating an exploitable condition that can be leveraged by network-adjacent attackers. The vulnerability's severity is amplified by the fact that it does not require authentication, making it particularly dangerous as any attacker within the network range can potentially exploit it. This type of vulnerability falls under CWE-121, which describes stack-based buffer overflow conditions where insufficient boundary checking allows attackers to overwrite adjacent memory locations, potentially including return addresses and function pointers.
The technical exploitation of this vulnerability occurs through the telnetd service that listens on port 23, which serves as the primary attack surface for this particular flaw. When the cmsCli_authenticate function processes user input, it fails to validate the input length against the fixed-size buffer capacity, allowing an attacker to overflow the stack buffer and overwrite critical program execution elements. The attack vector is particularly concerning because the telnetd service typically runs with elevated privileges, and successful exploitation can result in code execution with root-level privileges. This privilege escalation capability aligns with ATT&CK technique T1068, which covers 'Exploitation for Privilege Escalation' and represents a common attack pattern where initial access leads to elevated system privileges. The vulnerability's impact extends beyond simple code execution as it enables attackers to gain complete control over the affected router, potentially allowing them to modify network configurations, intercept traffic, or use the device as a pivot point for further attacks within the network infrastructure.
The operational impact of CVE-2023-34285 is substantial given the widespread deployment of NETGEAR RAX30 routers and the nature of the vulnerability. Network-adjacent attackers can leverage this flaw to establish persistent access to affected networks, potentially leading to long-term compromise of network security. The vulnerability's exploitation requires minimal prerequisites since no authentication is needed, making it particularly attractive to threat actors seeking to compromise network infrastructure. Organizations utilizing these routers face significant risk as attackers can use this vulnerability to perform various malicious activities including but not limited to network reconnaissance, data exfiltration, and establishing backdoors for future access. The fact that this vulnerability affects a shared library used by the telnetd service means that the impact extends beyond just the router itself, potentially affecting the broader network ecosystem that relies on proper authentication mechanisms. Security professionals should consider this vulnerability in their threat modeling exercises as it represents a potential entry point for sophisticated attacks that could compromise entire network domains.
Mitigation strategies for CVE-2023-34285 should prioritize immediate action to address the vulnerability through firmware updates provided by NETGEAR, as the vendor has likely released patches to resolve the buffer overflow condition. Network administrators should disable unnecessary services including telnetd where possible, as this reduces the attack surface and limits the exposure to this particular vulnerability. Implementing network segmentation and access control measures can help limit the impact of successful exploitation by preventing lateral movement within the network. Additionally, monitoring network traffic for unusual activity on port 23 and implementing intrusion detection systems can help identify potential exploitation attempts. Organizations should also consider disabling telnet services entirely and migrating to more secure alternatives such as SSH for remote administration purposes. The vulnerability highlights the importance of proper input validation and buffer management in embedded systems, and serves as a reminder of the critical need for robust security practices in network infrastructure devices. Security teams should conduct thorough vulnerability assessments to identify other potentially vulnerable services or components within their network infrastructure that may exhibit similar patterns of insecure coding practices.