CVE-2022-35519 in WN572HP3
Summary
by MITRE • 08/11/2022
WAVLINK WN572HP3, WN533A8, WN530H4, WN535G3, WN531P3 firewall.cgi has no filtering on parameter add_mac, which leads to command injection in page /cli_black_list.shtml.
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Analysis
by VulDB Data Team • 09/04/2022
The vulnerability identified as CVE-2022-35519 affects several WAVLINK wireless router models including WN572HP3, WN533A8, WN530H4, WN535G3, and WN531P3. This issue resides within the firewall.cgi script which handles MAC address management functionality. The flaw manifests as a critical command injection vulnerability that occurs when the add_mac parameter is processed without proper input validation or sanitization. The vulnerability specifically impacts the /cli_black_list.shtml page where user-supplied MAC addresses are accepted for blacklisting purposes, creating a direct pathway for malicious actors to execute arbitrary commands on the affected devices.
The technical implementation of this vulnerability stems from insufficient parameter filtering within the firewall.cgi script. When administrators or users submit MAC addresses through the web interface, the system fails to validate or sanitize the add_mac parameter before incorporating it into system commands. This lack of input validation creates a classic command injection scenario where attacker-controlled data can be interpreted as executable commands by the underlying operating system. The vulnerability is particularly dangerous because it allows remote code execution without requiring authentication, as the affected web interface is accessible to unauthenticated users. This type of vulnerability maps directly to CWE-77 and CWE-94, which classify command injection and code injection flaws respectively, and aligns with ATT&CK technique T1059.001 for command and scripting interpreter.
The operational impact of this vulnerability is severe and far-reaching for affected organizations and individuals. Remote attackers can exploit this vulnerability to gain full administrative control over the affected routers, potentially leading to complete network compromise. The injected commands can be used to establish persistent backdoors, modify router configurations, redirect network traffic, or even install malware on the device. Given that these are consumer and small office routers, they often serve as the primary gateway for network access and may be configured with default credentials or weak security settings, making them attractive targets for exploitation. The vulnerability could enable attackers to create persistent access points, monitor network traffic, or use the compromised device as a launching pad for further attacks against internal networks. Organizations with multiple affected devices face significant risk of widespread network compromise, particularly in environments where these routers are deployed without proper network segmentation or monitoring.
Mitigation strategies for CVE-2022-35519 should prioritize immediate action through firmware updates provided by WAVLINK, as the manufacturer likely released patches addressing this specific vulnerability. Network administrators should implement network segmentation to isolate affected devices from critical infrastructure, particularly by placing them in separate network zones with limited access to sensitive systems. Additional protective measures include disabling unnecessary web interfaces and services, implementing strict firewall rules to restrict access to the affected devices, and conducting thorough network monitoring for suspicious activity. Regular security assessments should be performed to identify other potentially vulnerable devices within the network infrastructure, as similar vulnerabilities may exist in other network equipment. The vulnerability highlights the critical importance of input validation and proper sanitization of user-supplied data in web applications, particularly in embedded systems where security considerations may be overlooked during development. Organizations should also consider implementing network intrusion detection systems to monitor for exploitation attempts and maintain detailed logs of all administrative activities on network devices to facilitate incident response efforts.