CVE-2019-20749 in D7800
Summary
by MITRE
Certain NETGEAR devices are affected by stored XSS. This affects D7800 before 1.0.1.47, EX6100v2 before 1.0.1.76, EX6150v2 before 1.0.1.76, R7500v2 before 1.0.3.38, R7800 before 1.0.2.52, R8900 before 1.0.4.12, R9000 before 1.0.4.12, WN2000RPTv3 before 1.0.1.32, WN3000RPv3 before 1.0.2.70, and WN3100RPv2 before 1.0.0.66.
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Analysis
by VulDB Data Team • 05/31/2024
The vulnerability identified as CVE-2019-20749 represents a critical stored cross-site scripting flaw affecting multiple NETGEAR router models, including popular consumer and enterprise-grade devices. This security weakness allows attackers to inject malicious scripts into the device's web interface that persist across user sessions, making it particularly dangerous for network infrastructure components. The affected devices span several product lines including the D7800, EX6100v2, EX6150v2, R7500v2, R7800, R8900, R9000, WN2000RPTv3, WN3000RPv3, and WN3100RPv2 models, all of which are vulnerable due to insufficient input validation and output sanitization within their web management interfaces. The vulnerability is classified under CWE-79 as a classic stored XSS flaw, where malicious code is stored on the server and executed when legitimate users access the affected pages. This weakness falls squarely within the ATT&CK framework under T1566.001 for Phishing and T1071.004 for Application Layer Protocol: DNS, as attackers can leverage the vulnerability to redirect users to malicious sites or steal session cookies.
The technical implementation of this vulnerability stems from the devices' failure to properly sanitize user input submitted through web forms and configuration interfaces. When administrators or users enter data into fields such as device names, network settings, or configuration parameters, the system does not adequately filter or escape special characters that could be interpreted as HTML or JavaScript code. This allows an attacker to craft malicious payloads that are stored within the device's configuration database or web interface elements. The stored nature of the vulnerability means that once the malicious script is injected, it will execute every time any user accesses the affected web pages, making it particularly insidious for network administrators who might unknowingly trigger the malicious code. The vulnerability affects firmware versions prior to the specified patches, indicating that NETGEAR has acknowledged and addressed the issue in subsequent releases, though the lack of patch availability for older devices leaves many users exposed.
The operational impact of CVE-2019-20749 extends beyond simple script execution, as it can enable attackers to perform a range of malicious activities including session hijacking, credential theft, and redirection to phishing sites. Network administrators who access the device interfaces may unknowingly execute malicious code that steals their authentication tokens or redirects them to attacker-controlled sites. The vulnerability particularly threatens enterprise environments where multiple administrators may access the same network devices, as a single compromised interface can provide attackers with persistent access to the entire network infrastructure. Additionally, the stored nature of the XSS allows attackers to maintain access even after the initial exploitation, as the malicious code remains embedded within the device's configuration until manually removed or the device is reset to factory defaults. This persistent access capability aligns with ATT&CK technique T1078.004 for Valid Accounts: Cloud Accounts, as attackers can potentially use stolen credentials to maintain long-term access to network resources. The vulnerability also poses significant risk to consumer networks, where unauthorized access could lead to complete network compromise and potential data exfiltration.
Mitigation strategies for CVE-2019-20749 primarily focus on firmware updates and network segmentation. The most effective immediate solution involves upgrading all affected NETGEAR devices to the latest firmware versions that contain patches addressing the XSS vulnerability. Organizations should conduct comprehensive inventory audits to identify all vulnerable devices within their network infrastructure and prioritize remediation efforts accordingly. Network segmentation and access controls should be implemented to limit administrative access to these devices, reducing the attack surface for potential exploitation. Regular monitoring of device interfaces for suspicious entries or unexpected changes can help detect exploitation attempts before they succeed. Additional protective measures include implementing network-based intrusion detection systems that can identify malicious traffic patterns associated with XSS attacks, as well as establishing strict access controls and multi-factor authentication for all administrative interfaces. The vulnerability also highlights the importance of secure coding practices and input validation, particularly for network infrastructure devices that handle user-supplied data through web interfaces. Organizations should consider deploying web application firewalls to filter malicious requests and implement regular security assessments to identify similar vulnerabilities in other network components. These mitigation strategies align with the NIST Cybersecurity Framework's Protect function, specifically focusing on defensive measures against malicious code and unauthorized access to critical network infrastructure.