CVE-2022-40942 in TX3
Summary
by MITRE • 09/28/2022
Tenda TX3 US_TX3V1.0br_V16.03.13.11 is vulnerable to stack overflow via compare_parentcontrol_time.
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Analysis
by VulDB Data Team • 10/25/2022
The vulnerability identified as CVE-2022-40942 affects Tenda TX3 US_TX3V1.0br_V16.03.13.11 firmware versions and represents a critical stack overflow condition that can be exploited through the compare_parentcontrol_time function. This issue resides within the router's web interface handling mechanism, specifically targeting the parent control time comparison functionality. The stack overflow vulnerability occurs when the device processes user-supplied input without proper bounds checking, allowing malicious actors to overwrite adjacent memory locations on the stack. Such vulnerabilities typically arise from insufficient input validation and buffer management practices during firmware development, creating potential entry points for remote code execution or system compromise.
The technical flaw manifests when the compare_parentcontrol_time function processes time-related parameters provided through web interface requests. This function likely handles parent control scheduling configurations where users specify time windows for device access restrictions. When malformed or excessively long input data is submitted to this function, the stack buffer becomes overflowed, potentially corrupting return addresses, saved registers, and other critical stack memory segments. The vulnerability is classified as a stack-based buffer overflow under CWE-121, which directly maps to the ATT&CK technique T1059.007 for command and scripting interpreter. The exploitation of this vulnerability can lead to arbitrary code execution with the privileges of the web server process, typically running with administrative rights on the device.
The operational impact of this vulnerability extends beyond simple system instability, as it enables remote attackers to gain unauthorized access to the router's administrative interface. Successful exploitation could allow attackers to modify network configurations, disable security features, redirect traffic, or establish persistent backdoors. The vulnerability is particularly concerning because it affects a widely deployed consumer-grade router model, potentially exposing thousands of devices to remote compromise. Attackers could leverage this vulnerability to create botnets, conduct man-in-the-middle attacks, or use the compromised devices as launching points for further network infiltration. The nature of the stack overflow makes this a high-severity issue under CVSS scoring criteria, with potential for complete system compromise and persistent access.
Mitigation strategies for CVE-2022-40942 should prioritize immediate firmware updates from Tenda, as the vendor has likely released patches addressing this specific vulnerability. Network administrators should implement network segmentation to limit exposure of these devices to untrusted networks, while also monitoring for suspicious traffic patterns that might indicate exploitation attempts. Additional defensive measures include disabling unnecessary web management interfaces, implementing strong access controls, and regularly auditing device configurations. The vulnerability highlights the importance of secure coding practices and input validation in embedded systems, aligning with security standards such as those recommended by the OWASP Internet of Things Project and the NIST Cybersecurity Framework. Organizations should also consider implementing network intrusion detection systems that can identify exploitation attempts targeting known vulnerabilities in networking equipment.