CVE-2019-20721 in D7800
Summary
by MITRE
Certain NETGEAR devices are affected by stored XSS. This affects D7800 before 1.0.1.47, EX2700 before 1.0.1.48, EX6100v2 before 1.0.1.76, EX6150v2 before 1.0.1.76, EX6200v2 before 1.0.1.72, EX6400 before 1.0.2.136, EX7300 before 1.0.2.136, 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, WN3000RPv2 before 1.0.0.68, WN3000RPv3 before 1.0.2.70, WN3100RPv2 before 1.0.0.66, WNDR4300v2 before 1.0.0.58, WNDR4500v3 before 1.0.0.58, WNR2000v5 before 1.0.0.66, XR450 before 2.3.2.32, and XR500 before 2.3.2.32.
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Analysis
by VulDB Data Team • 05/31/2024
This vulnerability represents a critical stored cross-site scripting flaw that affects numerous NETGEAR wireless routers and networking devices across multiple product lines. The vulnerability stems from insufficient input validation and output encoding within the web interface of these devices, allowing attackers to inject malicious scripts that persist in the device's storage and execute when other users access the affected web-based management interface. The affected models span several generations of NETGEAR routers including the D7800, EX series, R7500v2, R7800, R8900, R9000, and various WN and XR series devices, with specific version thresholds indicating the scope of impacted firmware releases.
The technical implementation of this vulnerability allows an attacker to inject malicious JavaScript code through input fields that are not properly sanitized before being stored and subsequently rendered in the web interface. When legitimate users access the device management page, the stored script executes in their browser context, potentially enabling session hijacking, credential theft, or redirection to malicious sites. This represents a classic stored XSS attack pattern where the malicious input is permanently saved on the server and executed against users who view the affected content. The vulnerability falls under CWE-79 which specifically addresses Cross-site Scripting flaws, and aligns with ATT&CK technique T1059.007 for Scripting, particularly targeting the execution of malicious code through web interfaces.
The operational impact of this vulnerability extends beyond simple browser-based attacks, as compromised routers can serve as entry points for broader network infiltration. An attacker who successfully exploits this vulnerability could potentially gain unauthorized access to the device's administrative functions, modify network configurations, redirect traffic, or establish persistent access points within the network. The widespread deployment of these affected devices across both residential and enterprise environments amplifies the potential impact, as many users may not regularly update their firmware or may be unaware of the security risks. The vulnerability's persistence through device reboots and its ability to affect multiple device types within the NETGEAR product line indicates a systemic security flaw in the web interface implementation.
Mitigation strategies should focus on immediate firmware updates from NETGEAR, which address the input validation gaps and implement proper output encoding for all user-supplied data. Network administrators should also implement monitoring for suspicious web traffic patterns and consider network segmentation to limit the potential damage from compromised devices. Additional defensive measures include disabling web management interfaces when not actively needed, implementing strong authentication mechanisms, and regularly auditing device configurations. The vulnerability highlights the importance of secure coding practices and proper input validation, particularly in web-based administrative interfaces that handle user input. Organizations should also consider implementing network access controls and intrusion detection systems to monitor for exploitation attempts, as the attack vector is relatively simple to execute and can be automated at scale.