CVE-2022-34576 in WN535 G3
Summary
by MITRE • 07/26/2022
A vulnerability in /cgi-bin/ExportAllSettings.sh of WAVLINK WN535 G3 M35G3R.V5030.180927 allows attackers to execute arbitrary code via a crafted POST request.
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Analysis
by VulDB Data Team • 08/27/2022
The vulnerability identified as CVE-2022-34576 represents a critical remote code execution flaw within the WAVLINK WN535 G3 M35G3R.V5030.180927 router firmware. This issue specifically affects the /cgi-bin/ExportAllSettings.sh script which serves as a command-line interface for exporting router configuration settings. The vulnerability arises from insufficient input validation and sanitization mechanisms within the web application layer that processes HTTP POST requests containing user-supplied data. Attackers can exploit this weakness by crafting malicious POST requests that manipulate the script's parameters, ultimately leading to unauthorized code execution on the affected device.
The technical implementation of this vulnerability stems from improper handling of user input within the CGI script execution environment. When the ExportAllSettings.sh script processes incoming POST data, it fails to properly validate or sanitize the parameters passed through the web interface. This lack of input sanitization creates an environment where malicious payloads can be injected directly into the command execution chain. The flaw aligns with CWE-77 and CWE-94 categories, specifically representing a command injection vulnerability that allows attackers to execute arbitrary system commands with the privileges of the web server process. The vulnerability operates at the application layer and can be exploited remotely without requiring authentication, making it particularly dangerous for networked devices.
The operational impact of this vulnerability extends beyond simple code execution to encompass complete system compromise and potential lateral movement within network environments. Once an attacker successfully exploits this vulnerability, they gain full administrative control over the router, enabling them to modify network configurations, redirect traffic, establish backdoors, or use the device as a pivot point for attacking other networked systems. The device's role as a network gateway makes it an attractive target for attackers seeking to maintain persistent access or conduct man-in-the-middle attacks against internal network traffic. This vulnerability directly maps to ATT&CK technique T1059.001 for command and scripting interpreter and T1021.001 for remote services, as it enables attackers to execute commands remotely through the web interface.
Mitigation strategies for CVE-2022-34576 require immediate firmware updates from WAVLINK to address the input validation issues within the ExportAllSettings.sh script. Organizations should implement network segmentation to isolate affected devices and monitor for suspicious traffic patterns that might indicate exploitation attempts. Network administrators should also consider disabling unnecessary web management interfaces and implementing firewall rules that restrict access to the affected CGI endpoints. The vulnerability highlights the importance of proper input validation and the principle of least privilege in embedded device security. Additionally, regular security audits of network infrastructure components and maintaining up-to-date firmware repositories are essential practices to prevent similar vulnerabilities from being exploited in production environments.