CVE-2022-28561 in AX12
Summary
by MITRE • 05/03/2022
There is a stack overflow vulnerability in the /goform/setMacFilterCfg function in the httpd service of Tenda ax12 22.03.01.21_cn router. An attacker can obtain a stable shell through a carefully constructed payload
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Analysis
by VulDB Data Team • 05/05/2022
The vulnerability identified as CVE-2022-28561 represents a critical stack overflow flaw within the Tenda ax12 22.03.01.21_cn router firmware, specifically affecting the httpd service component. This issue resides in the /goform/setMacFilterCfg function which processes incoming HTTP requests through the web interface. The stack overflow occurs when the router fails to properly validate input parameters sent to this specific function, creating an exploitable condition that allows arbitrary code execution. The vulnerability demonstrates characteristics consistent with CWE-121, stack-based buffer overflow, where insufficient bounds checking permits attackers to overwrite adjacent memory locations on the stack.
The technical exploitation of this vulnerability requires careful crafting of a payload that exceeds the allocated buffer space within the setMacFilterCfg function. When the httpd service processes a malicious request containing oversized input data, the stack memory layout becomes corrupted, potentially allowing an attacker to overwrite return addresses and function pointers. This memory corruption enables privilege escalation from a regular web user to root shell access, providing complete system compromise. The attack vector operates through the web interface, making it accessible to remote attackers without requiring physical access to the device or authentication credentials. The vulnerability's impact extends beyond simple code execution to full system control, aligning with ATT&CK technique T1059.007 for command and scripting interpreter and T1068 for exploit for privilege escalation.
The operational consequences of this vulnerability pose significant risks to network security and device integrity within the affected Tenda ax12 router models. Once exploited, attackers gain persistent access to the device, enabling them to modify network configurations, intercept traffic, establish backdoors, or use the compromised device as a launching point for attacks against other networked systems. The vulnerability affects not only individual devices but also creates potential for widespread compromise when multiple devices within the same network are running the vulnerable firmware version. Network administrators face challenges in identifying compromised devices, as the exploitation may not immediately produce obvious signs of compromise, and the device continues to function normally while providing unauthorized access to attackers. The presence of this vulnerability in a consumer-grade router exposes end-users to risks including data theft, network infiltration, and potential use in distributed denial-of-service attacks.
Mitigation strategies for CVE-2022-28561 should prioritize immediate firmware updates from Tenda, as the vendor has likely released patches addressing this specific vulnerability. Organizations should implement network monitoring to detect anomalous traffic patterns that may indicate exploitation attempts, particularly focusing on unusual requests to the /goform/setMacFilterCfg endpoint. Network segmentation and access controls can limit the potential impact if a device becomes compromised, while regular security audits should verify that all network devices are running patched firmware versions. The vulnerability highlights the importance of secure coding practices, particularly input validation and buffer management, as recommended by OWASP and NIST guidelines. Security teams should also consider implementing intrusion detection systems that can identify and block malicious payloads targeting known vulnerabilities in web services and embedded systems. Given the nature of the vulnerability, network administrators should also consider temporarily disabling unnecessary web services or implementing web application firewalls to protect against exploitation attempts.