CVE-2024-3907 in AC500
Summary
by MITRE • 04/17/2024
A vulnerability was found in Tenda AC500 2.0.1.9(1307). It has been rated as critical. This issue affects the function formSetCfm of the file /goform/setcfm. The manipulation of the argument funcpara1 leads to stack-based buffer overflow. The attack may be initiated remotely. The exploit has been disclosed to the public and may be used. The associated identifier of this vulnerability is VDB-261143. 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 • 01/18/2025
The vulnerability identified as CVE-2024-3907 represents a critical stack-based buffer overflow in the Tenda AC500 router firmware version 2.0.1.9(1307) affecting the web-based management interface. This flaw resides within the formSetCfm function located in the /goform/setcfm file path, which serves as a critical component for handling configuration parameters through the web interface. The vulnerability manifests when the funcpara1 argument is manipulated, allowing an attacker to exceed the bounds of a stack-allocated buffer and potentially overwrite adjacent memory locations. The attack vector is remote, meaning exploitation can occur without physical access to the device, making this particularly dangerous for network-connected IoT devices. The vulnerability has been publicly disclosed and is actively being exploited according to the VDB-261143 identifier, indicating that threat actors have already developed working exploits for this flaw. This represents a significant security risk for users who have not patched their firmware versions, as the vulnerability allows for arbitrary code execution capabilities through stack overflow exploitation.
The technical implementation of this vulnerability aligns with CWE-121, which describes stack-based buffer overflow conditions where insufficient bounds checking allows attackers to overwrite stack memory. The attack surface is particularly concerning because it targets the web interface configuration functions that are accessible to remote users with proper authentication or potentially without authentication depending on the specific implementation. The exploitation process likely involves sending a specially crafted HTTP request containing malformed data in the funcpara1 parameter that causes the buffer overflow when processed by the vulnerable function. This type of vulnerability falls under the ATT&CK technique T1210 - Exploitation of Remote Services, specifically targeting network services that handle user input without proper validation. The stack-based nature of the overflow means that attackers can potentially overwrite return addresses, function pointers, or other critical stack variables to redirect execution flow and achieve arbitrary code execution on the affected device.
The operational impact of CVE-2024-3907 extends beyond simple remote code execution, as compromised routers can serve as persistent footholds for broader network attacks. An attacker who successfully exploits this vulnerability could gain complete control over the router's operations, potentially enabling them to modify network configurations, redirect traffic through malicious proxies, or establish persistent backdoors for future access. The Tenda AC500 device, being a consumer-grade router, typically operates in unsecured environments where users may not regularly update firmware, making this vulnerability particularly attractive to threat actors. The lack of vendor response to early disclosure attempts compounds the risk, as users remain unaware of the vulnerability for extended periods while attackers develop and deploy exploits. This vulnerability particularly affects enterprise and home networks that rely on Tenda devices, potentially allowing attackers to pivot from the compromised router to access internal network resources, including sensitive servers, workstations, or other connected IoT devices. The remote exploitation capability means that attackers can target these devices from anywhere on the internet, making the attack surface extremely broad and difficult to monitor or defend against.
Mitigation strategies for CVE-2024-3907 must prioritize immediate firmware updates from Tenda if available, though the vendor's lack of response suggests this may not be forthcoming. Network administrators should implement strict firewall rules to restrict access to the router's web management interface from untrusted networks, particularly blocking access to the vulnerable /goform/setcfm endpoint. Network segmentation and monitoring can help detect anomalous traffic patterns that may indicate exploitation attempts, including unusual HTTP request parameters or malformed data in web interface communications. Organizations should conduct thorough network assessments to identify all affected Tenda AC500 devices and implement temporary security measures such as disabling unnecessary web services or implementing network access control lists that prevent external access to the device management interfaces. For devices that cannot be immediately updated, consider implementing network-based intrusion detection systems that can detect and alert on known exploit patterns targeting this specific vulnerability. The lack of vendor response underscores the importance of proactive security measures and maintaining awareness of third-party device vulnerabilities, as relying solely on vendor patches may leave systems exposed for extended periods. Security teams should also consider implementing device fingerprinting and monitoring solutions that can identify and alert on potentially compromised network devices that may be acting as command and control nodes for broader attacks.