CVE-2024-3908 in AC500
Summary
by MITRE • 04/17/2024
A vulnerability classified as critical has been found in Tenda AC500 2.0.1.9(1307). Affected is the function formWriteFacMac of the file /goform/WriteFacMac. The manipulation of the argument mac leads to command injection. It is possible to launch the attack remotely. The exploit has been disclosed to the public and may be used. The identifier of this vulnerability is VDB-261144. 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-2024-3908 represents a critical command injection flaw within the Tenda AC500 wireless router firmware version 2.0.1.9(1307). This security weakness resides in the formWriteFacMac function located within the /goform/WriteFacMac file, which serves as a critical interface for device management operations. The vulnerability specifically manifests when the mac argument parameter is manipulated, creating an avenue for arbitrary command execution within the router's operating system. The affected device architecture processes user-supplied input without adequate sanitization or validation, allowing malicious actors to inject OS commands directly through the web interface.
This command injection vulnerability operates at a fundamental level within the router's web application framework, where input validation mechanisms fail to properly filter or escape user-provided MAC address data. The flaw enables remote exploitation without requiring authentication, as the vulnerable endpoint accepts input through standard web requests that can be initiated from any network location. The absence of proper input sanitization creates a direct pathway for attackers to execute arbitrary commands on the underlying operating system, potentially gaining full administrative control over the device. The vulnerability's classification as critical stems from its remote exploitability and the severe privileges that can be gained through successful exploitation, which aligns with CWE-77 attack patterns related to command injection vulnerabilities.
The operational impact of this vulnerability extends beyond simple device compromise, as it provides attackers with complete control over the affected router's functionality and network access. Once exploited, an attacker can manipulate network traffic, redirect DNS queries, disable security features, or establish persistent backdoors within the network infrastructure. The vulnerability affects the router's factory MAC address writing functionality, which typically should only be accessible through legitimate administrative processes but can now be exploited by unauthorized parties. This represents a significant threat to network security since routers serve as primary gateways and often control critical network operations including firewall settings, DHCP services, and NAT configurations.
Security professionals should note that this vulnerability has been publicly disclosed and is actively being exploited in the wild, as indicated by the VDB-261144 identifier and the lack of vendor response to early disclosure attempts. The absence of vendor acknowledgment creates additional risk for affected organizations as no official patches or mitigations are currently available. Network defenders must implement immediate defensive measures including network segmentation, firewall rules blocking access to the vulnerable endpoint, and monitoring for suspicious network traffic patterns. The vulnerability's exploitation aligns with ATT&CK techniques categorized under privilege escalation and command execution, specifically targeting T1059.001 for command and scripting interpreter execution. Organizations should consider implementing network-based intrusion detection systems to identify exploitation attempts and establish monitoring protocols for anomalous requests to the /goform/WriteFacMac endpoint.
The broader implications of this vulnerability highlight the critical need for proper input validation and secure coding practices in embedded network devices. The flaw demonstrates how insufficient sanitization of user inputs can lead to complete system compromise, particularly in devices with limited security resources and outdated firmware. Given that the vendor has not responded to disclosure notifications, affected organizations should prepare for potential emergency patching procedures or consider replacing vulnerable devices with secured alternatives. The vulnerability also underscores the importance of maintaining current firmware versions and implementing network access controls to limit exposure to such remote attack vectors. Organizations should conduct comprehensive network assessments to identify all affected devices and implement temporary mitigations while awaiting official vendor responses or patches to address this critical security weakness.