CVE-2019-20076 in DL4323
Summary
by MITRE
On Netis DL4323 devices, XSS exists via the form2Ddns.cgi username parameter (DynDns settings of the Dynamic DNS Configuration).
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Analysis
by VulDB Data Team • 03/18/2024
The vulnerability identified as CVE-2019-20076 represents a cross-site scripting flaw within the Netis DL4323 network device firmware that specifically affects the Dynamic DNS Configuration section. This issue manifests through the form2Ddns.cgi web interface component where the username parameter fails to properly sanitize user input, creating an avenue for malicious actors to inject arbitrary script code into the device's web-based management interface. The vulnerability resides in the device's handling of Dynamic DNS settings, which are commonly used to maintain consistent network connectivity through dynamic IP address changes.
The technical exploitation of this vulnerability occurs when an attacker crafts malicious input containing script code within the username field of the DynDns configuration form. When the device processes this input and displays it back in the web interface without proper output encoding or validation, the embedded scripts execute within the context of a victim's browser session. This allows attackers to potentially steal session cookies, redirect users to malicious sites, or perform actions on behalf of authenticated users. The vulnerability is classified as a classic reflected cross-site scripting issue under CWE-79, which specifically addresses the improper sanitization of user-controllable data within web applications.
The operational impact of this vulnerability extends beyond simple script execution, as it compromises the integrity of the device's web management interface and potentially exposes the entire network to further attacks. An attacker could leverage this vulnerability to gain unauthorized access to the device configuration, modify network settings, or establish persistent access points within the network infrastructure. The attack surface is particularly concerning given that the vulnerability affects a core network device used for dynamic DNS configuration, which is often maintained by network administrators with elevated privileges. This scenario aligns with ATT&CK technique T1059.007 for scripting and T1566.001 for credential harvesting, as the vulnerability enables both code execution and potential credential theft through session hijacking.
Mitigation strategies for this vulnerability should include immediate firmware updates from Netis to address the input validation flaw in the form2Ddns.cgi component. Network administrators should also implement network segmentation to limit access to management interfaces and establish proper access controls through firewall rules that restrict direct access to device management ports. Additional protective measures include implementing web application firewalls to filter malicious input patterns and conducting regular security assessments of network infrastructure components. The vulnerability demonstrates the importance of input validation in embedded web interfaces and highlights the need for comprehensive security testing of network device management systems. Organizations should also consider implementing monitoring solutions to detect unusual traffic patterns that might indicate exploitation attempts, particularly targeting known vulnerable components within network infrastructure devices.