CVE-2024-4249 in i21
Summary
by MITRE • 04/27/2024
A vulnerability was found in Tenda i21 1.0.0.14(4656). It has been classified as critical. Affected is the function formwrlSSIDget of the file /goform/wifiSSIDget. 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. The identifier of this vulnerability is VDB-262140. 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
The vulnerability identified as CVE-2024-4249 represents a critical stack-based buffer overflow flaw in Tenda i21 router firmware version 1.0.0.14(4656). This security defect resides within the web interface component of the device, specifically in the formwrlSSIDget function located in the /goform/wifiSSIDget file. The vulnerability manifests when an attacker manipulates the ssidIndex argument, which serves as the primary attack vector for exploiting this memory corruption issue. The flaw stems from inadequate input validation and bounds checking within the router's web form processing logic, creating an exploitable condition that allows arbitrary code execution through remote network access.
The technical implementation of this vulnerability aligns with CWE-121 Stack-based Buffer Overflow, which occurs when a program writes more data to a fixed-length buffer located on the stack than the buffer can hold. The attack surface is particularly concerning as it enables remote exploitation without requiring authentication or physical access to the device. The stack-based nature of this overflow means that attackers can overwrite adjacent memory locations including return addresses, function pointers, and other critical program state information. This provides attackers with the capability to redirect program execution flow and potentially achieve complete system compromise through code injection attacks.
The operational impact of this vulnerability extends beyond simple denial of service or data theft, as it creates a persistent backdoor for attackers to gain unauthorized control of network infrastructure. Once exploited, the compromised router can serve as a pivot point for lateral movement within local networks, enabling attackers to access connected devices, intercept network traffic, or establish persistent command and control channels. The public disclosure of this exploit increases the risk profile significantly, as it provides threat actors with readily available attack tools and techniques. The lack of vendor response to early disclosure attempts compounds the severity, leaving users without official patches or mitigation guidance during the active exploitation period.
Organizations and individuals should immediately implement network segmentation strategies to isolate affected devices from critical infrastructure and sensitive data systems. Network monitoring should be enhanced to detect anomalous traffic patterns that may indicate exploitation attempts, particularly focusing on unusual requests to the /goform/wifiSSIDget endpoint. The most effective immediate mitigation involves disabling unnecessary web management interfaces and implementing firewall rules that restrict access to the router's administrative ports from untrusted networks. Additionally, network administrators should consider implementing intrusion detection systems with signatures specifically targeting this vulnerability, as well as maintaining detailed network traffic logs for forensic analysis. The vulnerability demonstrates the critical importance of firmware security updates and vendor communication in maintaining network security postures.