CVE-2021-20847 in Wi-Fi STATION SH-52A
Summary
by MITRE • 12/01/2021
Cross-site scripting vulnerability in Wi-Fi STATION SH-52A (38JP_1_11G, 38JP_1_11J, 38JP_1_11K, 38JP_1_11L, 38JP_1_26F, 38JP_1_26G, 38JP_1_26J, 38JP_2_03B, and 38JP_2_03C) allows a remote unauthenticated attacker to inject an arbitrary script via WebUI of the device.
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Analysis
by VulDB Data Team • 12/04/2021
The CVE-2021-20847 vulnerability represents a critical cross-site scripting flaw affecting the Wi-Fi STATION SH-52A device series, specifically versions 38JP_1_11G through 38JP_1_11L and 38JP_1_26F through 38JP_1_26J, along with 38JP_2_03B and 38JP_2_03C models. This vulnerability resides within the device's web-based user interface, creating a significant security risk for organizations relying on these wireless access points for network infrastructure. The flaw allows remote attackers to execute malicious scripts against unsuspecting users who interact with the device's web management interface, potentially compromising the entire network ecosystem.
This cross-site scripting vulnerability stems from inadequate input validation and output encoding within the device's web server implementation. The affected models utilize a web-based management interface that fails to properly sanitize user-supplied input parameters before rendering them in web responses. Attackers can exploit this weakness by crafting malicious script payloads and injecting them through various input fields accessible via the web UI, including configuration parameters, login credentials, or other user-controllable data entry points. The vulnerability specifically manifests when the device processes and displays user input without sufficient sanitization, creating an environment where attacker-controlled scripts can execute in the context of the victim's browser session.
The operational impact of CVE-2021-20847 extends beyond simple script execution, as it provides attackers with a foothold for more sophisticated attacks within the network infrastructure. An unauthenticated attacker can leverage this vulnerability to steal session cookies, redirect users to malicious sites, deface the web interface, or even execute arbitrary commands on the device if additional vulnerabilities exist. The attack surface is particularly concerning for organizations using these devices in enterprise environments, as compromised access points can serve as launching points for lateral movement, credential theft, or man-in-the-middle attacks against network traffic. The vulnerability affects the device's authentication mechanism by potentially allowing attackers to bypass security controls or manipulate the web interface to gain unauthorized access to network configuration settings.
Security practitioners should consider this vulnerability in the context of the MITRE ATT&CK framework, where it maps to techniques involving client-side attacks and credential access through web-based exploitation. The vulnerability aligns with CWE-79, which specifically addresses cross-site scripting flaws in web applications, making it a direct threat to web application security. Organizations should prioritize immediate remediation through firmware updates provided by the vendor, as the vulnerability affects multiple device variants within the same product line, indicating a systemic issue rather than an isolated defect. The attack vector requires no authentication, making it particularly dangerous as it can be exploited by anyone with network access to the device's web interface, potentially enabling widespread compromise of wireless network infrastructure across multiple organizational domains.
Mitigation strategies should include immediate firmware updates from the vendor, network segmentation to limit access to device management interfaces, and implementation of web application firewalls to detect and block malicious script injection attempts. Additionally, organizations should conduct comprehensive vulnerability assessments to identify all affected devices within their network infrastructure, as the multiple model variants suggest a broader product line vulnerability. Network monitoring should be enhanced to detect unusual traffic patterns that may indicate exploitation attempts, while administrative access to these devices should be restricted to authorized personnel only. The vulnerability underscores the importance of secure coding practices and input validation in network infrastructure devices, particularly those with web-based management interfaces that are frequently exposed to external network traffic.