CVE-2022-35517 in WN572HP3
Summary
by MITRE • 08/11/2022
WAVLINK WN572HP3, WN533A8, WN530H4, WN535G3, WN531P3 adm.cgi has no filtering on parameters: web_pskValue, wl_Method, wlan_ssid, EncrypType, rwan_ip, rwan_mask, rwan_gateway, ppp_username, ppp_passwd and ppp_setver, which leads to command injection in page /wizard_router_mesh.shtml.
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Analysis
by VulDB Data Team • 09/04/2022
The vulnerability identified as CVE-2022-35517 affects several WAVLINK wireless router models including WN572HP3, WN533A8, WN530H4, WN535G3, and WN531P3. This issue stems from inadequate input validation within the administrative web interface of these devices, specifically in the adm.cgi script that handles various network configuration parameters. The flaw manifests through the absence of proper parameter filtering for critical variables including web_pskValue, wl_Method, wlan_ssid, EncrypType, rwan_ip, rwan_mask, rwan_gateway, ppp_username, ppp_passwd, and ppp_setver. These parameters are processed without sanitization or validation, creating a pathway for malicious actors to inject arbitrary commands into the system.
The technical exploitation of this vulnerability occurs through the /wizard_router_mesh.shtml page which accepts the unfiltered parameters and subsequently executes them within the device's command processing pipeline. This command injection vulnerability allows attackers to execute arbitrary system commands with the privileges of the web server process, potentially leading to complete system compromise. The flaw represents a classic command injection vulnerability that aligns with CWE-77, which specifically addresses improper neutralization of special elements used in commands. The vulnerability is particularly dangerous because it affects the administrative interface of network devices, potentially enabling attackers to gain unauthorized access to network infrastructure and modify critical routing configurations.
The operational impact of this vulnerability extends beyond simple command execution, as it can lead to full system compromise of the affected routers. Attackers can leverage this vulnerability to modify network settings, establish persistent backdoors, redirect network traffic, or even use the compromised devices as part of botnet operations. The affected devices are commonly deployed in residential and small office environments, making them attractive targets for attackers seeking to establish footholds within networks. This vulnerability also aligns with ATT&CK technique T1059.001, which covers command and scripting interpreter execution, and T1566.001, which addresses spearphishing via social engineering. The lack of input validation creates a persistent risk that remains active until the device firmware is updated, potentially exposing networks to ongoing threats.
Mitigation strategies for this vulnerability require immediate firmware updates from WAVLINK, as the manufacturer should provide patches that implement proper input validation and sanitization for all parameters processed by the adm.cgi script. Network administrators should also implement network segmentation to limit access to administrative interfaces and monitor for suspicious network activity that might indicate exploitation attempts. Additionally, the principle of least privilege should be applied by restricting administrative access to only trusted users and systems. The vulnerability demonstrates the critical importance of input validation in web applications and network device interfaces, as highlighted in industry best practices for secure coding and network security. Organizations should also consider implementing intrusion detection systems to monitor for exploitation attempts and maintain updated vulnerability databases to quickly identify and respond to similar issues in their network infrastructure.