CVE-2019-11418 in TEW-632BRP
Summary
by MITRE
apply.cgi on the TRENDnet TEW-632BRP 1.010B32 router has a buffer overflow via long strings to the SOAPACTION:HNAP1 interface.
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Analysis
by VulDB Data Team • 09/06/2023
The CVE-2019-11418 vulnerability represents a critical buffer overflow flaw in the apply.cgi component of TRENDnet TEW-632BRP routers running firmware version 1.010B32. This vulnerability specifically targets the SOAPACTION:HNAP1 interface, which is part of the Home Network Administration Protocol implementation used by the router for remote management operations. The issue arises from inadequate input validation within the router's web application interface, where the system fails to properly sanitize or limit the length of data submitted through the SOAP action header. This architectural weakness creates a condition where malicious actors can exploit the vulnerability by sending excessively long strings to the affected parameter, causing the application to overwrite adjacent memory regions beyond the allocated buffer boundaries. The vulnerability is particularly concerning as it exists within the router's core management interface, providing potential attackers with direct access to critical system functions.
The technical exploitation of this buffer overflow vulnerability follows standard attack patterns that align with CWE-121, which describes "Stack-based Buffer Overflow" conditions where insufficient bounds checking allows attackers to overwrite adjacent memory locations. The attack vector specifically targets the router's HTTP server component that processes incoming SOAP requests, where the apply.cgi script handles administrative commands. When an attacker crafts a malicious request with an oversized SOAPACTION header, the router's processing routine fails to validate the input length, leading to memory corruption that can result in arbitrary code execution or complete system compromise. The vulnerability's impact is amplified by the fact that the affected interface is designed for remote administration, meaning attackers could potentially exploit this issue from outside the local network without requiring physical access to the device.
The operational consequences of CVE-2019-11418 extend beyond simple denial of service scenarios, as the buffer overflow could enable full system compromise through code execution. Attackers who successfully exploit this vulnerability could gain root access to the router's operating system, allowing them to modify network configurations, install malicious firmware, or establish persistent backdoors. The compromised router would then become part of a botnet, potentially used for launching distributed denial of service attacks or serving as a pivot point for further network infiltration. This vulnerability directly relates to ATT&CK technique T1059.007, which covers "Command and Scripting Interpreter: PowerShell," as the compromised router could be used to execute malicious commands and scripts. Additionally, the flaw demonstrates characteristics of T1021.001, "Remote Services: Remote Desktop Protocol," in terms of unauthorized remote access capabilities, though the specific implementation uses HTTP-based protocols rather than RDP.
Mitigation strategies for this vulnerability should focus on immediate firmware updates from TRENDnet, as the vendor has likely released patches addressing the buffer overflow condition. Network segmentation and firewall rules should be implemented to restrict access to the router's management interfaces, particularly limiting access to trusted IP addresses and blocking external connections to the affected SOAP interface. Organizations should also consider implementing intrusion detection systems that can monitor for unusual traffic patterns or attempts to exploit known buffer overflow signatures. The vulnerability highlights the importance of input validation and bounds checking in embedded network devices, aligning with security best practices outlined in NIST SP 800-160 and OWASP Top Ten. Regular security audits of network infrastructure, including thorough vulnerability assessments of all connected devices, should be conducted to identify similar issues in other router models or firmware versions. Additionally, network administrators should implement network monitoring to detect anomalous behavior that might indicate exploitation attempts, particularly focusing on unusual HTTP request patterns or attempts to access administrative interfaces from unexpected locations.