CVE-2017-17738 in Digital Signage
Summary
by MITRE
The BrightSign Digital Signage (4k242) device (Firmware 6.2.63 and below) allows renaming and modifying files via /tools.html.
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Analysis
by VulDB Data Team • 08/24/2024
The BrightSign Digital Signage device running firmware version 6.2.63 and earlier contains a critical security vulnerability that allows unauthorized file manipulation through the web interface. This vulnerability exists within the /tools.html endpoint which provides administrative functions without proper authentication mechanisms. The flaw enables attackers to rename and modify files on the device, potentially compromising the entire digital signage system and its content integrity.
This vulnerability represents a classic authorization bypass issue that falls under CWE-285, which deals with improper authorization in web applications. The device fails to implement proper access controls for administrative functions, allowing any remote attacker to perform file operations that should be restricted to authenticated administrators only. The lack of input validation and authentication checks creates an attack surface that directly violates the principle of least privilege and proper access control implementation.
The operational impact of this vulnerability extends beyond simple file manipulation capabilities. Attackers could potentially replace digital signage content with malicious media files, modify system configuration files, or even introduce backdoors into the device. This compromise could lead to denial of service conditions where legitimate content cannot be displayed, or more sinisterly, where the device becomes a vector for distributing malware to connected networks. The attack surface is particularly concerning given that digital signage systems often operate in public spaces and may be connected to corporate networks, making them attractive targets for adversaries seeking persistent access points.
The vulnerability also aligns with ATT&CK technique T1059 which involves executing malicious code through command-line interfaces. Attackers could leverage this flaw to upload and execute arbitrary code on the device, potentially leading to complete system compromise. Additionally, the issue demonstrates poor secure coding practices and inadequate security testing of web interfaces in embedded systems. Organizations using BrightSign devices should immediately update to firmware versions that address this vulnerability, implement network segmentation to limit access to administrative interfaces, and conduct thorough security assessments of their digital signage infrastructure. The vulnerability highlights the critical need for proper authentication and authorization controls in all web-accessible interfaces of embedded systems, particularly those deployed in public environments where physical security may be limited.