CVE-2019-20673 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-2019-20673 represents a critical stored cross-site scripting flaw affecting multiple NETGEAR router models including RBR20, RBS20, RBK20, RBR40, RBS40, RBK40, RBR50, RBS50, and RBK50. This vulnerability resides in the web-based management interface of these devices and allows attackers to inject malicious JavaScript code that persists in the device's memory. The flaw specifically impacts firmware versions prior to 2.3.5.26 for the RBR20, RBS20, and RBK20 models, and prior to 2.3.5.30 for the RBR40, RBS40, RBK40, RBR50, RBS50, and RBK50 models. The stored XSS vulnerability enables attackers to execute arbitrary code within the context of the victim's browser session, potentially leading to complete compromise of the affected network infrastructure.
The technical implementation of this vulnerability stems from inadequate input validation and output encoding within the web interface components of these NETGEAR devices. When users interact with the management console and input data into fields that are not properly sanitized, the malicious scripts are stored in the device's configuration or logs and subsequently executed when other users view the affected pages. This creates a persistent threat vector where attackers can establish backdoors, steal session cookies, redirect users to malicious sites, or perform other malicious activities. The vulnerability aligns with CWE-79 which specifically addresses cross-site scripting flaws, and represents a classic case of insecure data handling in web applications. The attack surface is particularly concerning as these are network infrastructure devices that typically operate with elevated privileges and have access to sensitive network configuration data.
The operational impact of this vulnerability extends far beyond simple script execution, as compromised routers can serve as entry points for broader network attacks. An attacker who successfully exploits this vulnerability can potentially gain unauthorized access to the entire network segment controlled by the compromised router, enabling them to monitor traffic, redirect requests, or even establish persistent access through the device. The stored nature of the XSS means that the attack can affect multiple users over time, making it particularly dangerous in enterprise environments where multiple administrators might access the same device management interface. This vulnerability also aligns with ATT&CK technique T1071.004 which covers application layer protocol: DNS, and T1046 which addresses network service scanning, as compromised routers can be used to launch further attacks within the network. The impact is compounded by the fact that these devices often serve as the primary gateway for network traffic, making them prime targets for attackers seeking to establish persistent access or conduct reconnaissance activities.
Mitigation strategies for CVE-2019-20673 primarily involve immediate firmware updates from NETGEAR to versions 2.3.5.26 or 2.3.5.30 depending on the specific model. Organizations should also implement network segmentation to limit the potential impact of compromised devices and establish monitoring procedures to detect unusual network behavior that might indicate exploitation. Network administrators should disable unnecessary web management interfaces and implement strict access controls to minimize exposure. Additionally, regular vulnerability assessments should be conducted to identify other potentially vulnerable network infrastructure devices, as this vulnerability demonstrates the importance of proper input validation and output encoding in web applications. The remediation process should include thorough testing of updated firmware to ensure that the security patches do not introduce compatibility issues with existing network configurations. Security teams should also consider implementing network traffic monitoring solutions that can detect anomalous patterns consistent with XSS attack payloads and establish incident response procedures specifically tailored to address router compromise scenarios.