CVE-2018-19922 in C1000A
Summary
by MITRE
Persistent Cross-Site Scripting (XSS) in the advancedsetup_websiteblocking.html Website Blocking page of the Actiontec C1000A router with firmware through CAC004-31.30L.95 allows a remote attacker to inject arbitrary HTML into the Website Blocking page by inserting arbitrary HTML into the 'TodUrlAdd' URL parameter in a /urlfilter.cmd POST request.
If you want to get the best quality for vulnerability data then you always have to consider VulDB.
Analysis
by VulDB Data Team • 04/18/2020
The CVE-2018-19922 vulnerability represents a critical persistent cross-site scripting flaw discovered in the Actiontec C1000A router model, specifically affecting firmware versions up to CAC004-31.30L.95. This vulnerability resides within the advancedsetup_websiteblocking.html page which manages website blocking functionality, making it a significant concern for network security administrators who rely on such filtering mechanisms to protect their networks from malicious content. The flaw stems from inadequate input validation and sanitization within the router's web interface, creating a persistent XSS attack vector that allows remote adversaries to execute arbitrary HTML code within the context of the router's administrative interface.
The technical exploitation of this vulnerability occurs through a specific manipulation of the 'TodUrlAdd' URL parameter within a POST request to the /urlfilter.cmd endpoint. Attackers can craft malicious payloads that, when submitted through this parameter, are stored persistently within the router's configuration and subsequently executed whenever the website blocking page is accessed. This persistent nature means that the malicious code remains active even after the initial injection, making it particularly dangerous as it can affect any user who accesses the router's web interface, including legitimate administrators. The vulnerability directly maps to CWE-79 which defines cross-site scripting as the improper sanitization of user-provided data, and more specifically to CWE-80 which addresses the failure to properly encode output to prevent XSS attacks. The attack vector operates through the standard HTTP protocol with the router's web interface serving as the attack surface.
The operational impact of CVE-2018-19922 extends beyond simple script execution, as it provides attackers with a foothold within the router's administrative interface that could lead to complete network compromise. An attacker who successfully exploits this vulnerability could potentially modify website blocking rules, redirect traffic to malicious sites, or even gain access to other router configuration settings that might not be directly exposed through the website blocking functionality. This vulnerability falls under the ATT&CK technique T1059.007 which covers the use of script-based attacks and T1071.004 which covers application layer protocol usage. The persistent nature of the XSS allows for long-term surveillance and manipulation of network traffic filtering, potentially enabling attackers to bypass security measures or redirect users to phishing sites while maintaining access to the compromised router.
Mitigation strategies for this vulnerability should begin with immediate firmware updates from Actiontec to address the XSS flaw, as this represents the most direct and effective solution. Network administrators should also implement network segmentation to limit access to the router's administrative interface, ensuring that only authorized personnel can reach the web interface. Additional protective measures include implementing web application firewalls that can detect and block malicious payloads targeting known XSS patterns, and conducting regular security audits of router configurations to identify any unauthorized modifications. The vulnerability also highlights the importance of secure coding practices in embedded systems, particularly the need for comprehensive input validation and output encoding within web interfaces. Organizations should consider implementing network monitoring solutions that can detect anomalous traffic patterns associated with XSS attacks, and establish incident response procedures specifically designed to handle router compromise scenarios. Given the persistent nature of the vulnerability, it is crucial that administrators verify the effectiveness of their mitigations by attempting to reproduce the original vulnerability after implementing security controls.