CVE-2017-17737 in Digital Signage
Summary
by MITRE
The BrightSign Digital Signage (4k242) device (Firmware 6.2.63 and below) has XSS via the REF parameter to /network_diagnostics.html or /storage_info.html.
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Analysis
by VulDB Data Team • 08/24/2024
The BrightSign Digital Signage device running firmware versions 6.2.63 and below contains a cross-site scripting vulnerability that affects the network diagnostics and storage information web interfaces. This vulnerability specifically targets the REF parameter in two critical endpoints: /network_diagnostics.html and /storage_info.html. The flaw allows remote attackers to inject malicious scripts into the web interface through crafted input parameters, potentially enabling unauthorized access to sensitive system information and user data.
The technical implementation of this vulnerability stems from inadequate input validation and output sanitization within the web server component of the BrightSign firmware. When the REF parameter is processed by the device's web interface, it fails to properly escape or filter user-supplied data before rendering it in the browser context. This creates an opportunity for attackers to execute malicious JavaScript code within the context of the authenticated user's session, leveraging the device's administrative privileges. The vulnerability falls under CWE-79 which specifically addresses cross-site scripting flaws, and represents a classic case of insecure input handling in web applications. The attack surface is particularly concerning as it affects the device's diagnostic interfaces which are typically accessible to administrators and may contain sensitive system information.
The operational impact of this vulnerability extends beyond simple script execution as it can lead to complete device compromise and unauthorized access to the digital signage network. An attacker could exploit this vulnerability to gain persistent access to the device, potentially leading to content manipulation, unauthorized data exfiltration, or use of the device as a pivot point for attacking other networked systems. The vulnerability is particularly dangerous in enterprise environments where multiple BrightSign devices are deployed, as it could enable attackers to establish a foothold within the digital signage infrastructure and potentially escalate privileges to gain full administrative control over the affected devices. This aligns with ATT&CK technique T1059.007 for command and scripting interpreter and T1071.004 for application layer protocol.
Mitigation strategies should focus on immediate firmware updates to versions that address this vulnerability, as BrightSign has released patches to resolve the XSS issue. Network segmentation and access controls should be implemented to limit direct access to the device interfaces, particularly the vulnerable endpoints. Additionally, administrators should consider implementing web application firewalls to detect and block malicious requests targeting these specific parameters. Regular security assessments of digital signage infrastructure should include testing for similar input validation vulnerabilities, as this represents a common attack vector in IoT and embedded systems. The vulnerability demonstrates the critical importance of proper input sanitization in embedded web interfaces and highlights the need for comprehensive security testing of all web-accessible components in networked devices.