CVE-2024-4243 in Tenda
Summary
by MITRE • 04/27/2024
A vulnerability classified as critical has been found in Tenda W9 1.0.0.7(4456). Affected is the function formwrlSSIDset of the file /goform/wifiSSIDset. The manipulation of the argument ssidIndex leads to stack-based buffer overflow. It is possible to launch the attack remotely. The exploit has been disclosed to the public and may be used. VDB-262134 is the identifier assigned to this vulnerability. NOTE: The vendor was contacted early about this disclosure but did not respond in any way.
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Analysis
by VulDB Data Team • 01/28/2025
This critical vulnerability exists in the Tenda W9 router firmware version 1.0.0.7(4456) within the wireless configuration management interface. The flaw resides in the formwrlSSIDset function located in the /goform/wifiSSIDset file, representing a stack-based buffer overflow condition that occurs when processing the ssidIndex argument. The vulnerability's classification as critical stems from its remote exploitability and the fact that a working exploit has been publicly disclosed, making it immediately actionable by threat actors. This particular implementation flaw allows attackers to manipulate the ssidIndex parameter in a manner that overflows the allocated stack buffer, potentially leading to arbitrary code execution or system compromise. The vulnerability's exposure through the web interface means that an unauthenticated attacker can remotely trigger the buffer overflow by sending specially crafted requests to the affected router.
The technical execution of this vulnerability follows a classic stack-based buffer overflow pattern where insufficient input validation permits an attacker to write beyond the bounds of allocated memory. The ssidIndex parameter, when manipulated beyond acceptable limits, causes the program to overwrite adjacent stack memory locations, potentially corrupting return addresses or other critical program state information. This type of vulnerability maps directly to CWE-121 Stack-based Buffer Overflow, which is categorized under the broader category of CWE-119 Improper Access to Memory Locations. The attack vector is particularly dangerous because it requires no authentication and can be executed through standard web browser interactions with the router's management interface, making it highly accessible to both skilled and less skilled attackers. According to the ATT&CK framework, this vulnerability aligns with T1210 Exploitation of Remote Services and T1059 Command and Scripting Interpreter, as it enables remote code execution through web-based exploitation.
The operational impact of this vulnerability extends beyond simple system compromise to encompass complete network infrastructure control. An attacker who successfully exploits this vulnerability could gain administrative access to the router, potentially enabling them to modify network configurations, intercept traffic, redirect users to malicious sites, or establish persistent backdoors. The remote nature of the exploit eliminates the need for physical access to the device, significantly expanding the attack surface. Additionally, the lack of vendor response to early disclosure attempts creates a concerning scenario where affected users remain unaware of the critical risk without official patches or mitigation guidance. This vulnerability could also serve as a stepping stone for more sophisticated attacks, as compromised routers often become part of larger botnet operations or provide attackers with initial access to internal networks. The absence of vendor communication further compounds the risk, as users may continue to operate vulnerable devices without knowledge of the exposure.
Immediate mitigation strategies should focus on network segmentation and monitoring to detect exploitation attempts. Organizations should implement network access control lists to restrict access to affected routers from unauthorized networks and deploy intrusion detection systems to monitor for known exploit patterns targeting this specific vulnerability. The most effective long-term solution requires firmware updates from Tenda, though given the vendor's lack of response, users should consider alternative router solutions or implement additional network security controls. Network administrators should also conduct comprehensive inventory audits to identify all affected Tenda W9 devices within their environments and consider disabling unnecessary web management interfaces until patches are available. Security monitoring should include checking for unusual network traffic patterns or unauthorized configuration changes that might indicate exploitation attempts, as the vulnerability's public disclosure increases the likelihood of active exploitation attempts across the internet.