CVE-2021-45673 in R7000
Summary
by MITRE • 12/26/2021
Certain NETGEAR devices are affected by stored XSS. This affects R7000 before 1.0.11.110, R7900 before 1.0.4.30, R8000 before 1.0.4.62, RAX200 before 1.0.3.106, R7000P before 1.3.3.140, RAX80 before 1.0.3.106, R6900P before 1.3.3.140, and RAX75 before 1.0.3.106.
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Analysis
by VulDB Data Team • 12/30/2021
The vulnerability CVE-2021-45673 represents a critical stored cross-site scripting flaw affecting multiple NETGEAR router models, including the R7000, R7900, R8000, RAX200, R7000P, RAX80, R6900P, and RAX75 series. This vulnerability resides in the web-based management interfaces of these devices, where user input is not properly sanitized before being stored and subsequently rendered in web pages. The flaw allows an attacker to inject malicious scripts that persist in the device's memory, making it a stored XSS vulnerability rather than a reflected one. The affected firmware versions indicate that this issue has been present for several years, suggesting that many devices in the field remain vulnerable to exploitation.
The technical implementation of this vulnerability stems from inadequate input validation and output encoding within the router's web administration interface. When administrators or users enter data through web forms or configuration fields, the system fails to properly sanitize this input before storing it in the device's configuration database. When the web interface subsequently retrieves and displays this data, the malicious scripts execute in the context of other users who access the management interface, particularly those with administrative privileges. This creates a persistent threat vector where a single successful injection can compromise the device and potentially the entire network it protects. The vulnerability aligns with CWE-79, which specifically addresses cross-site scripting flaws, and represents a classic example of how insecure input handling can lead to persistent security breaches in network infrastructure devices.
The operational impact of this vulnerability extends far beyond simple script execution, as it provides attackers with the capability to escalate privileges and gain unauthorized access to critical network infrastructure. An attacker who successfully exploits this vulnerability can potentially modify router configurations, redirect traffic, steal administrative credentials, or even establish persistent backdoors within the network. The stored nature of the vulnerability means that the malicious payload remains active even after the initial injection, creating a long-term threat that can persist until the device is rebooted or the firmware is updated. This poses significant risks to enterprise and home networks alike, as compromised routers can serve as entry points for broader network infiltration, lateral movement, and data exfiltration. The vulnerability particularly affects the ATT&CK technique T1071.004, which involves application layer protocol usage for command and control communications, and T1566.001, which encompasses phishing attacks targeting network infrastructure.
Mitigation strategies for CVE-2021-45673 require immediate firmware updates from NETGEAR to address the root cause of the vulnerability. Organizations should prioritize updating all affected router models to their latest firmware versions, which contain proper input sanitization and output encoding mechanisms. Network administrators should also implement network segmentation and access controls to limit exposure of these devices to untrusted networks, while monitoring for suspicious activity in router management interfaces. Additional defensive measures include disabling unnecessary web management interfaces, implementing strong authentication mechanisms, and conducting regular security audits of network infrastructure devices. The vulnerability demonstrates the importance of secure coding practices in embedded network devices and highlights the need for continuous security assessments of Internet of Things and networking equipment. Organizations should also consider implementing intrusion detection systems that can identify suspicious web traffic patterns or attempts to exploit known vulnerabilities in network infrastructure devices.