CVE-2019-20665 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.
Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.
Analysis
by VulDB Data Team • 05/26/2024
The vulnerability identified as CVE-2019-20665 represents a critical stored cross-site scripting flaw affecting multiple NETGEAR router models within the RBR, RBS, and RBK series. This security weakness allows attackers to inject malicious scripts into web interfaces that persist across user sessions, making it particularly dangerous for network infrastructure devices. The affected firmware versions span several generations of NETGEAR routers, indicating a widespread issue that impacts both consumer and small business networking equipment. The vulnerability specifically targets the web management interfaces of these devices, which are commonly accessed by network administrators and end users for configuration and monitoring purposes. Stored XSS vulnerabilities are classified under CWE-079 as they involve the execution of malicious scripts from stored data, making them distinct from reflected XSS attacks that require user interaction with malicious links. The impact extends beyond simple script execution since these devices serve as core networking infrastructure, potentially providing attackers with persistent access points for further network exploitation. The affected models include RBR20, RBS20, RBK20, RBR40, RBS40, RBK40, RBR50, RBS50, and RBK50, all running firmware versions prior to the specified patches. This vulnerability directly violates the principle of input validation and output encoding, as the web interfaces fail to properly sanitize user-supplied data before storing and rendering it back to users. Network administrators who rely on these devices for configuration management face significant risk since any input field that accepts user data could become an attack vector for malicious script injection. The stored nature of this vulnerability means that once an attacker successfully injects malicious code, it will execute every time a user accesses the affected web interface, regardless of whether they are the original attacker or subsequent legitimate users. This persistent threat makes the vulnerability particularly dangerous in multi-user environments where multiple administrators might access the same device configuration interface.
The technical exploitation of this vulnerability occurs through the web management interface of affected NETGEAR routers, where user input is not properly sanitized before being stored in the device's configuration or logging systems. Attackers can craft malicious payloads that, when submitted through web forms or configuration fields, get stored and subsequently executed whenever the web interface is accessed by any user. The vulnerability exploits the lack of proper input validation mechanisms and insufficient output encoding in the web server components of these routers. This allows attackers to inject malicious JavaScript code that can perform actions such as stealing session cookies, redirecting users to malicious sites, or even executing arbitrary commands on the device. The attack typically requires minimal user interaction beyond accessing the vulnerable web interface, making it particularly effective for social engineering campaigns. The exploitation chain often involves initial access through a compromised user session or direct web interface interaction, followed by the persistence of malicious scripts that can be triggered by any subsequent access to the device's configuration pages. This vulnerability can be leveraged to create a backdoor for persistent access or to exfiltrate sensitive configuration data from the affected routers. The attack vector aligns with ATT&CK technique T1059.007 for JavaScript execution and T1566 for credential harvesting through web interface manipulation. The persistence mechanism of stored XSS means that even after the initial exploitation, attackers can maintain access without requiring repeated user interaction, making this a significant threat to network security. The vulnerability's impact is amplified by the fact that these devices often serve as gateways to larger network infrastructures, potentially providing attackers with access to internal network resources.
The operational impact of CVE-2019-20665 extends far beyond simple script execution, as compromised routers can serve as persistent footholds for broader network attacks. Network administrators face the challenge of securing devices that may be unknowingly compromised, with malicious scripts potentially running in the background while administrators perform routine configuration tasks. The vulnerability can lead to complete network compromise when attackers leverage the stored XSS to redirect users to malicious sites or steal authentication credentials from the device management interface. Organizations that rely on these NETGEAR routers for network security may experience unauthorized access to their internal systems, as these devices often serve as the first line of defense in network infrastructure. The persistent nature of the vulnerability means that once exploited, attackers can maintain access for extended periods without requiring additional user interaction, making detection and remediation more difficult. This vulnerability particularly affects small to medium business networks where network administrators may not have the resources for continuous security monitoring or rapid patch deployment. The impact on network availability is significant since compromised devices may exhibit unexpected behavior, potentially leading to service disruptions or unauthorized network access. Security professionals must consider the potential for lateral movement through the network when these devices are compromised, as routers often control traffic flow between different network segments. The vulnerability also creates a risk for credential exposure, as attackers can capture authentication tokens or session data that could be used to access other network resources. The widespread nature of the affected devices means that organizations with multiple installations of these routers face a substantial security risk that requires coordinated patching efforts across their entire network infrastructure. The vulnerability's exploitation can result in complete loss of network control, as attackers can manipulate routing tables or configuration settings to redirect network traffic. Additionally, the compromised devices may become part of botnets or be used for launching attacks against other network resources, creating a broader security impact beyond the immediate affected organization. The remediation process requires careful planning and execution across all affected devices, as patching must be coordinated to avoid network disruptions while ensuring complete vulnerability remediation. Organizations should implement network monitoring to detect any suspicious activity that might indicate exploitation of this vulnerability, as the stored nature of the XSS makes it particularly difficult to detect through standard network traffic analysis. The vulnerability also highlights the importance of secure configuration practices and the need for regular security assessments of network infrastructure devices to identify and remediate similar weaknesses before they can be exploited by attackers.