CVE-2022-37809 in AC1206
Summary
by MITRE • 08/25/2022
Tenda AC1206 V15.03.06.23 was discovered to contain a stack overflow via the speed_dir parameter in the function formSetSpeedWan.
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Analysis
by VulDB Data Team • 08/25/2022
The vulnerability identified as CVE-2022-37809 affects the Tenda AC1206 router model running firmware version V15.03.06.23 and represents a critical stack overflow flaw that exists within the web management interface of the device. This vulnerability is particularly concerning as it resides in the formSetSpeedWan function which handles WAN speed configuration parameters, specifically targeting the speed_dir parameter. The stack overflow occurs when the device processes user-supplied input without adequate validation or bounds checking, creating an exploitable condition that could allow remote code execution or system compromise. The vulnerability is categorized under CWE-121 as a stack-based buffer overflow, which is a well-documented weakness in software development practices where insufficient input validation leads to memory corruption. This particular implementation flaw allows attackers to manipulate the device's memory layout through crafted input parameters, potentially leading to complete system control.
The technical exploitation of this vulnerability requires an attacker to send a specially crafted HTTP request to the router's web interface containing an oversized speed_dir parameter value. When the router's web server processes this malformed input within the formSetSpeedWan function, it fails to properly validate the input length against the allocated stack buffer space. This results in memory corruption that can be leveraged to overwrite return addresses, function pointers, or other critical memory locations within the execution stack. The attack surface is particularly broad as the vulnerability exists in the web management interface which is typically accessible over the network, making it remotely exploitable without requiring physical access to the device. According to the ATT&CK framework, this vulnerability maps to T1210 - Exploitation of Remote Services, where an adversary exploits a vulnerability in a service running on a remote system to gain unauthorized access. The impact extends beyond simple denial of service as this type of stack overflow can be weaponized to execute arbitrary code with the privileges of the web server process, potentially leading to full system compromise.
The operational impact of this vulnerability is significant for network administrators and end users who rely on Tenda routers for their networking infrastructure. Organizations using affected devices are at risk of unauthorized network access, data interception, or complete network disruption. The vulnerability affects not just individual devices but entire network segments that depend on these routers for connectivity, as compromised devices can serve as entry points for lateral movement within the network. The exploitation of this vulnerability aligns with ATT&CK technique T1071.004 - Application Layer Protocol: DNS, where compromised devices might be used to establish command and control channels or to redirect network traffic. Network security teams face increased risk of persistent threats as attackers can maintain long-term access to the network through this backdoor vulnerability. The vulnerability also represents a failure in secure software development practices, specifically in input validation and memory management, which are fundamental requirements for network device security. Organizations should consider implementing network segmentation and monitoring to detect anomalous behavior that might indicate exploitation attempts, as well as ensuring all network devices are updated to patched firmware versions.
The recommended mitigation strategies include immediate firmware updates from Tenda to address the stack overflow vulnerability, implementing network access controls to restrict access to the router management interface, and conducting thorough network security assessments to identify any potential exploitation attempts. Network administrators should also consider disabling unnecessary services and implementing firewall rules to limit access to the affected device. The vulnerability demonstrates the importance of regular firmware updates and vulnerability assessments in maintaining network security posture. Organizations should also implement security monitoring solutions that can detect abnormal traffic patterns or exploitation attempts targeting network infrastructure devices. Additionally, the incident highlights the need for robust input validation practices in all network device software development, emphasizing the importance of following secure coding guidelines and conducting thorough security testing before deployment. The vulnerability serves as a reminder of the critical importance of maintaining up-to-date network infrastructure and the potential consequences of running outdated firmware with known security flaws.