CVE-2022-35561 in Tenda
Summary
by MITRE • 08/12/2022
A stack overflow vulnerability exists in /goform/WifiMacFilterSet in Tenda W6 V1.0.0.9(4122) version, which can be exploited by attackers to cause a denial of service (DoS) via the index parameter.
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Analysis
by VulDB Data Team • 09/10/2022
This vulnerability resides in the Tenda W6 router firmware version 1.0.0.9(4122) within the /goform/WifiMacFilterSet endpoint, representing a critical stack overflow flaw that can be leveraged for remote denial of service attacks. The vulnerability specifically manifests when processing the index parameter, which lacks proper input validation mechanisms. The flaw allows attackers to craft malicious requests that overflow the stack buffer, potentially leading to arbitrary code execution or complete system crash. This type of vulnerability falls under CWE-121 Stack-based Buffer Overflow, which is classified as a fundamental memory safety issue that has been consistently exploited in network device firmware for years. The attack surface is particularly concerning given that the affected endpoint is part of the web-based administration interface, making it accessible over the network without requiring physical access to the device.
The technical exploitation of this vulnerability requires careful crafting of the index parameter to exceed the allocated stack buffer space, typically through sending a specially formatted HTTP request to the vulnerable endpoint. The stack overflow occurs because the firmware does not perform adequate bounds checking on user-supplied input before copying it into fixed-size buffers. This allows an attacker to overwrite adjacent memory locations, potentially corrupting the return address or other critical stack data structures. According to the ATT&CK framework, this vulnerability maps to T1210 Exploitation for Execution and T1499.004 Endpoint Denial of Service, as it enables attackers to disrupt the normal operation of the network device. The impact extends beyond simple denial of service since successful exploitation could potentially lead to complete system compromise, especially when combined with other vulnerabilities present in the firmware.
The operational impact of this vulnerability is significant for network administrators and end users who rely on Tenda W6 routers for their networking infrastructure. Devices running this firmware version become susceptible to remote exploitation, allowing attackers to render them completely non-functional without requiring authentication. The vulnerability affects the wireless access point functionality, which could disrupt network connectivity for all connected devices. Organizations with multiple affected devices face a substantial risk of widespread service disruption, particularly in environments where network reliability is critical. Network security teams must consider this vulnerability as part of their threat modeling, especially in scenarios where untrusted network traffic might reach the affected devices. The vulnerability's exploitation is relatively straightforward, requiring only basic web request crafting skills, making it a prime target for automated attack tools. Security researchers have noted that firmware vendors often fail to implement proper input validation in web interfaces, creating persistent attack vectors that remain unpatched for extended periods. This particular vulnerability demonstrates how legacy firmware code can contain fundamental security flaws that persist across multiple versions, highlighting the importance of regular firmware updates and security assessments. The lack of proper stack protection mechanisms in embedded systems like routers makes them particularly vulnerable to these types of buffer overflow attacks, which have been documented in numerous other network device vendors over the years.