CVE-2019-20675 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-2019-20675 represents a critical stored cross-site scripting flaw affecting several NETGEAR router models including RBR50 RBS50 and RBK50. This security weakness allows attackers to inject malicious scripts into web interfaces that persist and execute when other users access the affected devices. The vulnerability specifically impacts firmware versions prior to 2.3.5.30 across these router models, making them susceptible to persistent XSS attacks that can compromise user sessions and potentially lead to full device compromise. The affected devices operate within the consumer and small office networking space where users may have administrative access through web-based interfaces.
Stored XSS vulnerabilities occur when web applications fail to properly sanitize user input before storing and later rendering it without adequate escaping or encoding. In the context of network routers this means that when administrators or users enter data through web forms or configuration interfaces, malicious scripts can be injected and stored within the device's memory or configuration files. These scripts then execute whenever the affected web interface is accessed by legitimate users or administrators. The vulnerability manifests when the device's web server processes user-supplied data without proper validation and sanitization, allowing malicious payloads to be stored and executed in the context of the victim's browser session.
The operational impact of this vulnerability extends beyond simple script execution as it can enable attackers to perform a wide range of malicious activities. An attacker who successfully exploits this vulnerability could steal administrator credentials, modify device configurations, redirect users to malicious sites, or establish persistent access to the network. The stored nature of the vulnerability means that even after the initial injection, the malicious code continues to execute automatically whenever users access the affected web interface. This persistence makes the vulnerability particularly dangerous for network administrators who may unknowingly execute malicious code while performing routine maintenance tasks or troubleshooting network issues.
The vulnerability aligns with CWE-79 which defines cross-site scripting as a weakness where applications fail to properly validate or escape user-supplied input. From an attack perspective this flaw maps to multiple ATT&CK techniques including T1059 for command and script execution and T1566 for credential access through social engineering. The affected devices typically lack robust input validation mechanisms that would normally prevent such attacks, creating an attack surface where user-supplied data can be directly embedded into web responses without proper sanitization. Network security professionals should note that this vulnerability represents a critical risk in environments where router administrative interfaces are accessible from untrusted networks or where users may be susceptible to phishing attacks that could lead to exploitation.
Mitigation strategies for this vulnerability require immediate firmware updates to versions 2.3.5.30 or later where NETGEAR has implemented proper input validation and sanitization measures. Administrators should also implement network segmentation to limit access to router administrative interfaces and employ network monitoring solutions that can detect anomalous traffic patterns associated with XSS exploitation attempts. Additionally organizations should conduct regular security assessments of network infrastructure devices to identify similar vulnerabilities and ensure that all firmware updates are applied promptly. The security community should recognize this vulnerability as a prime example of why proper input validation and output encoding are critical components of secure web application development, particularly in network infrastructure devices that serve as gateways to enterprise networks.