CVE-2019-20671 in RBR20
Summary
by MITRE
Certain NETGEAR devices are affected by stored XSS. This affects RBR20 before 2.3.5.26, RBS20 before 2.3.5.26, RBK20 before 2.3.5.26, RBR40 before 2.3.5.30, RBS40 before 2.3.5.30, RBK40 before 2.3.5.30, 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 CVE-2019-20671 represents a stored cross-site scripting flaw affecting multiple NETGEAR router models including the RBR20, RBS20, RBK20, RBR40, RBS40, RBK40, RBR50, RBS50, and RBK50 series. This security weakness allows attackers to inject malicious scripts into the device's web interface that persist across user sessions, making it particularly dangerous for network infrastructure devices. The affected firmware versions prior to 2.3.5.26 for the 20 series and 2.3.5.30 for the 40 and 50 series indicate a widespread issue affecting several generations of NETGEAR wireless routers and access points. Stored XSS vulnerabilities are classified under CWE-79 in the Common Weakness Enumeration, which specifically addresses cross-site scripting flaws where malicious scripts are stored on the server and executed when users access the affected pages. The vulnerability exists due to insufficient input validation and output encoding within the web management interface of these devices, allowing attackers to inject malicious JavaScript code through parameters that are not properly sanitized before being rendered back to users.
The operational impact of this vulnerability extends beyond simple script execution, as these devices serve as critical network infrastructure components that often contain sensitive configuration data and administrative credentials. When exploited, the stored XSS attack can enable attackers to steal session cookies, redirect users to malicious sites, or perform actions on behalf of authenticated users within the router's management interface. This capability aligns with ATT&CK technique T1071.004 for application layer protocol: DNS, as attackers could potentially use the compromised interface to manipulate network settings or redirect traffic. The vulnerability is particularly concerning because these routers typically operate in residential and small business environments where network administrators may not regularly update firmware, creating extended exposure windows. The attack surface includes any user who accesses the router's web management interface, potentially affecting both legitimate administrators and unauthorized parties who gain access to the network.
Mitigation strategies for CVE-2019-20671 require immediate firmware updates to versions 2.3.5.26 or later for the affected RBR20, RBS20, and RBK20 models, and 2.3.5.30 or later for the RBR40, RBS40, RBK40, RBR50, RBS50, and RBK50 models. Network administrators should also implement network segmentation to limit access to the router management interfaces, restrict administrative access to specific IP addresses, and monitor for suspicious traffic patterns that might indicate exploitation attempts. Additional protective measures include disabling web management interfaces when not actively needed, implementing strong authentication mechanisms, and conducting regular security audits of network infrastructure devices. The vulnerability demonstrates the importance of proper input validation and output encoding in web applications, as recommended by OWASP Top 10 2017 category A03: Injection, which emphasizes the need for proper sanitization of user inputs to prevent XSS attacks. Organizations should also consider implementing network monitoring tools that can detect anomalous behavior in network infrastructure devices and establish regular patch management procedures to ensure timely deployment of security updates across all network equipment.