CVE-2019-20639 in RBR50
Summary
by MITRE
Certain NETGEAR devices are affected by stored XSS. This affects RBR50 before 2.3.5.30, RBS50 before 2.3.5.30, and RBK50 before 2.3.5.30.
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Analysis
by VulDB Data Team • 05/26/2024
The vulnerability identified as CVE-2019-20639 represents a critical stored cross-site scripting flaw affecting several NETGEAR router models including the RBR50, RBS50, and RBK50 series. This type of vulnerability falls under the Common Weakness Enumeration category CWE-79 which specifically addresses cross-site scripting attacks where malicious scripts are injected into web applications and then executed in the context of other users' browsers. The affected devices are particularly concerning as they represent network infrastructure components that serve as gateways for network traffic and user access to internal systems.
The technical implementation of this vulnerability stems from inadequate input validation and output encoding within the web-based management interfaces of these routers. When users interact with the affected devices through their web portals, the system fails to properly sanitize user-supplied data before storing and subsequently rendering it in web pages. This allows an attacker to inject malicious JavaScript code through various input fields such as device names, network settings, or configuration parameters. The stored nature of this vulnerability means that once the malicious payload is submitted and saved to the device's configuration, it will automatically execute whenever any user accesses the affected web interface, regardless of whether they are authenticated or not.
The operational impact of this vulnerability extends far beyond simple web application security concerns, as it fundamentally compromises the integrity of network infrastructure. Attackers can leverage this vulnerability to perform session hijacking, steal administrative credentials, redirect users to malicious sites, or even execute arbitrary commands on the affected devices. In a network environment, this could enable attackers to gain unauthorized access to internal systems, monitor network traffic, modify device configurations, or establish persistent backdoors. The vulnerability affects firmware versions prior to 2.3.5.30, indicating that organizations using these older versions face significant risk without proper patch management procedures in place. The attack surface is particularly wide since these devices are typically accessible from both internal networks and potentially from external interfaces, making them attractive targets for remote exploitation attempts.
Mitigation strategies for this vulnerability should prioritize immediate firmware updates to versions 2.3.5.30 or later, which contain the necessary patches to address the input validation gaps. Network administrators should also implement additional security controls such as restricting administrative access to these devices through firewall rules, implementing network segmentation to limit exposure, and monitoring for unusual network activity that might indicate exploitation attempts. The MITRE ATT&CK framework categorizes this vulnerability under the T1059.007 technique for "Command and Scripting Interpreter: JavaScript" as attackers can leverage the stored XSS to execute malicious JavaScript code within the browser context of authenticated users. Organizations should also consider implementing web application firewalls and regular security assessments to identify similar vulnerabilities in other network infrastructure components, as this type of flaw demonstrates the critical importance of proper input validation and output encoding in web applications that serve administrative functions.