CVE-2019-20664 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 identified as CVE-2019-20664 represents a critical stored cross-site scripting flaw affecting multiple NETGEAR router models within the RBR, RBS, and RBK series. This vulnerability stems from inadequate input validation and output encoding mechanisms within the web interface of affected devices, creating a persistent security weakness that allows attackers to inject malicious scripts into the device's configuration interface. The flaw specifically impacts firmware versions prior to the mentioned patches, with affected models including various RBR20, RBS20, RBK20, RBR40, RBS40, RBK40, RBR50, RBS50, and RBK50 devices. The stored nature of this XSS vulnerability means that malicious scripts persist in the device's configuration storage and execute whenever the vulnerable web interface is accessed by any user, including administrators.
The technical implementation of this vulnerability occurs through the web-based management interface of NETGEAR routers, where user-controllable input parameters are not properly sanitized before being stored and subsequently rendered back to users. When administrators or legitimate users access the device configuration pages, the malicious scripts embedded in the stored configuration data execute within the context of the user's browser session. This creates a persistent threat vector that can be exploited to hijack administrative sessions, steal session cookies, redirect users to malicious sites, or perform unauthorized configuration changes. The vulnerability maps directly to CWE-79, which defines cross-site scripting as a weakness where untrusted data is used to generate web pages without proper validation or escaping, and aligns with ATT&CK technique T1059.005 for command and scripting interpreter usage through web applications.
The operational impact of this vulnerability extends beyond simple script execution, as it provides attackers with a persistent foothold within network infrastructure. An attacker who successfully exploits this vulnerability can gain unauthorized access to router administrative interfaces, potentially leading to complete network compromise. The stored nature of the attack means that even after the initial exploitation, the malicious payload continues to execute whenever any user accesses the device configuration, making detection difficult and persistent access possible. This vulnerability particularly affects enterprise and home network environments where routers serve as critical infrastructure components, potentially enabling attackers to modify routing tables, redirect traffic, or establish persistent backdoors within the network. The attack surface is broad as multiple device models share the same vulnerability, and the exploitation requires minimal technical expertise since it leverages the legitimate web interface functionality.
Mitigation strategies for CVE-2019-20664 should prioritize immediate firmware updates to versions 2.3.5.26 or 2.3.5.30, depending on the specific device model, as provided by NETGEAR. Network administrators should also implement network segmentation and access controls to limit exposure of affected devices to untrusted users. Additional protective measures include monitoring network traffic for suspicious activity, implementing web application firewalls to detect and block XSS payloads, and conducting regular security assessments of network infrastructure. Organizations should also consider disabling web management interfaces when not actively needed and implementing strong authentication mechanisms including multi-factor authentication for administrative access. The vulnerability demonstrates the importance of proper input validation and output encoding in web applications, aligning with security best practices outlined in the OWASP Top Ten and NIST cybersecurity guidelines. Regular vulnerability scanning and patch management programs should be implemented to prevent similar issues in other network infrastructure components, as this vulnerability represents a common pattern of insufficient sanitization in web-based administrative interfaces.