CVE-2021-45663 in R7000
Summary
by MITRE • 12/26/2021
NETGEAR R7000 devices before 1.0.11.126 are affected by stored XSS.
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Analysis
by VulDB Data Team • 12/30/2021
The vulnerability CVE-2021-45663 represents a stored cross-site scripting flaw discovered in NETGEAR R7000 router devices running firmware versions prior to 1.0.11.126. This critical security weakness allows remote attackers to inject malicious scripts into the router's web interface that persist across user sessions and system reboots. The vulnerability specifically affects the device's handling of user-supplied input within administrative configuration parameters, creating a persistent vector for malicious code execution. Stored XSS vulnerabilities are particularly dangerous because the malicious scripts are saved on the server and executed whenever authorized users access the affected interface, making them more impactful than reflected XSS variants that require user interaction with crafted links.
The technical flaw stems from insufficient input validation and output sanitization within the router's web management interface. When administrators or authenticated users enter data into configurable fields, the system fails to properly encode or escape special characters that could be interpreted as HTML or JavaScript code. This allows attackers to inject malicious payloads that are subsequently stored in the device's configuration database. The vulnerability exists in the router's user interface processing logic where user inputs are directly rendered back to the browser without adequate security measures to prevent code injection attacks. The flaw enables attackers to execute arbitrary JavaScript code in the context of the victim's browser session, potentially compromising the entire network management interface.
The operational impact of this vulnerability is severe as it provides attackers with persistent access to the router's administrative functions. Once exploited, malicious actors can manipulate router settings, redirect traffic, modify firewall rules, and potentially gain unauthorized network access. The stored nature of the vulnerability means that even after the initial attack, the malicious code continues to execute every time the affected interface is accessed, making it particularly difficult to detect and remediate. Network administrators who regularly access the router's web interface become potential victims, as their browser sessions become compromised. The vulnerability also affects the integrity of the router's configuration management system, potentially allowing attackers to establish backdoors or persistently monitor network traffic through the compromised device.
Mitigation strategies for CVE-2021-45663 primarily focus on firmware updates and network segmentation. Device owners should immediately upgrade their NETGEAR R7000 routers to firmware version 1.0.11.126 or later, which includes proper input validation and output encoding mechanisms. Network administrators should also implement additional security controls such as restricting administrative access to trusted IP addresses, enabling multi-factor authentication where possible, and monitoring network traffic for suspicious patterns. The vulnerability aligns with CWE-79, which specifically addresses cross-site scripting flaws, and represents a significant risk under ATT&CK framework's T1071.004 technique for application layer protocol traffic shaping. Organizations should also consider implementing network monitoring solutions to detect potential exploitation attempts and maintain regular security assessments of their network infrastructure to identify similar vulnerabilities in other devices.