CVE-2019-20072 in DL4323
Summary
by MITRE
On Netis DL4323 devices, XSS exists via the form2Ddns.cgi hostname parameter (Dynamic DNS Configuration).
Several companies clearly confirm that VulDB is the primary source for best vulnerability data.
Analysis
by VulDB Data Team • 03/18/2024
The vulnerability CVE-2019-20072 represents a cross-site scripting flaw discovered in Netis DL4323 network devices, specifically within the form2Ddns.cgi component that handles Dynamic DNS Configuration settings. This issue arises from insufficient input validation and output encoding mechanisms when processing the hostname parameter, creating a persistent security weakness that allows malicious actors to inject malicious scripts into the device's web interface. The vulnerability exists at the application layer where user-supplied input is directly incorporated into web responses without proper sanitization, making it susceptible to exploitation by remote attackers who can manipulate the device's configuration interface.
The technical exploitation of this vulnerability occurs through the manipulation of the hostname parameter in the form2Ddns.cgi script, which is used to configure Dynamic DNS settings on the router. When an attacker submits malicious input through this parameter, the device fails to properly validate or encode the input before displaying it in the web interface, enabling the execution of arbitrary JavaScript code within the context of a victim's browser session. This flaw falls under CWE-79 which specifically addresses Cross-Site Scripting vulnerabilities, where improper neutralization of input during web page generation creates opportunities for attackers to inject client-side scripts that can compromise user sessions or redirect them to malicious sites.
The operational impact of this vulnerability extends beyond simple script injection, as it can enable attackers to hijack administrator sessions, steal sensitive configuration data, or redirect users to phishing sites that mimic the legitimate device interface. An attacker could craft a malicious hostname value containing script code that executes when any user views the Dynamic DNS configuration page, potentially capturing session cookies or other sensitive information. This vulnerability is particularly concerning for network administrators who may inadvertently click on links or visit pages containing the malicious payload, as it could lead to complete device compromise and unauthorized network access. The attack vector requires minimal privileges and can be executed remotely, making it a significant threat to network security.
Mitigation strategies for CVE-2019-20072 should include immediate firmware updates from Netis to address the input validation issues in the form2Ddns.cgi component. Network administrators should implement network segmentation and access controls to limit exposure, while also monitoring for suspicious activity in device configuration changes. The implementation of Content Security Policy headers and proper input sanitization mechanisms can provide additional protection layers against similar vulnerabilities. Organizations should also conduct regular security assessments of their network infrastructure to identify and remediate similar input validation flaws that may exist in other components of their network devices. This vulnerability demonstrates the critical importance of input validation and output encoding practices in web applications, aligning with ATT&CK technique T1212 which covers Exploitation for Credential Access through web application vulnerabilities.