CVE-2022-35522 in WN572HP3
Summary
by MITRE • 08/11/2022
WAVLINK WN572HP3, WN533A8, WN530H4, WN535G3, WN531P3 adm.cgi has no filtering on parameters: ppp_username, ppp_passwd, rwan_gateway, rwan_mask and rwan_ip, which leads to command injection in page /wan.shtml.
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Analysis
by VulDB Data Team • 09/04/2022
The vulnerability identified as CVE-2022-35522 affects several WAVLINK wireless router models including WN572HP3, WN533A8, WN530H4, WN535G3, and WN531P3. This represents a critical command injection flaw that exists within the administrative web interface of these devices. The vulnerability stems from inadequate input validation and sanitization within the adm.cgi script, which processes parameters related to WAN configuration settings. The affected parameters include ppp_username, ppp_passwd, rwan_gateway, rwan_mask, and rwan_ip, all of which are processed without proper filtering mechanisms that would prevent malicious input from being executed as system commands.
The technical implementation of this vulnerability allows an attacker to inject arbitrary commands through the web interface by manipulating the specified parameters in the /wan.shtml page. When these parameters are submitted to the adm.cgi script, the system fails to validate or sanitize the input before using it in system calls or command execution contexts. This lack of input validation creates a direct path for command injection attacks, where maliciously crafted input can be interpreted and executed by the underlying operating system. The vulnerability is particularly concerning because it affects administrative functions that control WAN connectivity, potentially allowing attackers to gain unauthorized access to network configurations and underlying system commands.
The operational impact of this vulnerability extends beyond simple command execution, as it provides attackers with potential access to critical network infrastructure components. An attacker who can successfully exploit this vulnerability could manipulate WAN settings, potentially redirecting network traffic through malicious gateways, altering routing configurations, or even gaining persistent access to the device. The vulnerability affects devices that are typically deployed in residential and small office environments, where such access could enable broader network compromise. Given that these parameters are used for configuring PPP authentication and WAN IP settings, successful exploitation could lead to unauthorized network access, data interception, or disruption of network services. The vulnerability aligns with CWE-77 and CWE-94 categories, representing command injection flaws that allow execution of arbitrary code.
Mitigation strategies for this vulnerability require immediate action from device administrators to update firmware to versions that address the input validation issues. Network segmentation and access controls should be implemented to limit access to administrative interfaces to trusted users only. The implementation of web application firewalls and input validation rules can provide additional protection layers. Regular security audits of network devices and monitoring for anomalous administrative activities should be conducted. Organizations should also consider implementing network access control measures that restrict direct access to administrative interfaces from untrusted networks. This vulnerability demonstrates the importance of proper input validation and sanitization in web applications, as highlighted by ATT&CK technique T1059.001 for command and scripting interpreter. Device vendors should implement comprehensive security testing including input validation checks and proper parameter sanitization before releasing firmware updates to prevent similar issues in future deployments.