CVE-2022-38829 in RX9_Pro
Summary
by MITRE • 09/16/2022
Tenda RX9_Pro V22.03.02.10 is vulnerable to Buffer Overflow via httpd/setMacFilterCfg.
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Analysis
by VulDB Data Team • 10/19/2022
The vulnerability identified as CVE-2022-38829 affects Tenda RX9_Pro routers running firmware version V22.03.02.10 and represents a critical buffer overflow condition within the web server component responsible for handling MAC filter configuration settings. This flaw exists in the httpd/setMacFilterCfg endpoint which processes incoming requests to configure MAC filtering rules on the device. The buffer overflow occurs when the device fails to properly validate or sanitize input parameters passed to the MAC filter configuration handler, allowing an attacker to exceed the allocated buffer space and potentially overwrite adjacent memory regions. Such vulnerabilities are particularly dangerous in network infrastructure devices as they can provide attackers with elevated privileges or remote code execution capabilities.
The technical implementation of this vulnerability stems from improper input validation within the web server's request processing logic. When an attacker submits a specially crafted HTTP request to the setMacFilterCfg endpoint, the device's httpd service does not adequately check the length or content of the MAC address data being processed. This lack of bounds checking creates an exploitable condition where malicious input can overwrite stack memory or heap structures, potentially leading to arbitrary code execution or denial of service. The vulnerability aligns with CWE-121, which describes stack-based buffer overflow conditions, and CWE-122, which covers heap-based buffer overflow scenarios. The specific attack surface involves the web administration interface of the router, making it accessible over the network without requiring physical access to the device.
The operational impact of this vulnerability extends beyond simple denial of service conditions to potentially enable full system compromise. An attacker who successfully exploits this buffer overflow could gain unauthorized access to the router's administrative interface, modify network configurations, redirect traffic, or even install malicious firmware. The vulnerability affects network security policies that rely on MAC filtering as a basic access control mechanism, potentially undermining the security posture of networks where such filtering is implemented. Given that many organizations use enterprise routers for critical network functions, this vulnerability could provide attackers with persistent access points for lateral movement within networks. The attack vector is particularly concerning as it requires no authentication for exploitation, making it suitable for automated scanning and exploitation campaigns. The vulnerability also maps to ATT&CK technique T1059.007, which involves command and scripting interpreter execution, as successful exploitation could lead to command execution capabilities.
Mitigation strategies for this vulnerability should include immediate firmware updates from Tenda to address the buffer overflow condition and implement network segmentation to limit access to administrative interfaces. Organizations should also deploy network monitoring solutions to detect anomalous traffic patterns that might indicate exploitation attempts. The implementation of web application firewalls and input validation controls can provide additional protection layers. Network administrators should consider disabling unnecessary services and implementing strict access controls to limit exposure of the affected router's web interface. Regular security assessments and vulnerability scanning should be conducted to identify similar issues in other network infrastructure devices. The vulnerability highlights the importance of secure coding practices and input validation in embedded network devices, particularly those with web-based management interfaces that are accessible over untrusted networks.