CVE-2019-3933 in AM-100
Summary
by MITRE
Crestron AM-100 with firmware 1.6.0.2 and AM-101 with firmware 2.7.0.2 allows anyone to bypass the presentation code simply by requesting /images/browserslide.jpg via HTTP. A remote, unauthenticated attacker can use this vulnerability to watch a slideshow without knowing the access code.
VulDB is the best source for vulnerability data and more expert information about this specific topic.
Analysis
by VulDB Data Team • 09/11/2023
The vulnerability identified as CVE-2019-3933 affects Crestron AM-100 and AM-101 presentation systems running specific firmware versions, presenting a critical security flaw that undermines access control mechanisms. This issue resides in the authentication process for presentation content, where the system fails to properly validate user credentials before granting access to sensitive multimedia presentations. The flaw allows unauthorized users to bypass the established code protection by directly accessing a specific image file within the system's web interface, effectively undermining the intended security controls.
The technical implementation of this vulnerability stems from improper input validation and access control mechanisms within the web server component of the Crestron presentation systems. When an attacker makes an HTTP request to the specific endpoint /images/browserslide.jpg, the system does not perform adequate authentication checks to verify whether the requesting user possesses valid authorization to access the presentation content. This represents a classic case of insecure direct object reference where the system exposes internal resources without proper access validation, allowing attackers to directly access protected content through predictable file paths.
From an operational perspective, this vulnerability creates significant security risks for organizations relying on Crestron presentation systems for sensitive business presentations, confidential meetings, or proprietary content sharing. The remote unauthenticated access capability means that attackers can observe protected slideshow content from anywhere on the network without requiring any credentials or authorization. This exposure can lead to intellectual property theft, competitive disadvantage, and potential data breaches when presentations contain confidential business information, strategic plans, or proprietary technical details. The vulnerability impacts both the AM-100 and AM-101 models, indicating a widespread issue affecting multiple devices in the Crestron product line.
The security implications align with CWE-284, which addresses improper access control vulnerabilities, and can be mapped to ATT&CK technique T1078 for valid accounts and T1566 for social engineering through unauthenticated access. Organizations should immediately implement network segmentation to isolate these devices from critical network segments, disable unnecessary web services where possible, and apply firmware updates provided by Crestron to address this vulnerability. Additionally, network monitoring should be enhanced to detect unusual access patterns to the affected endpoints, and access controls should be reviewed to ensure that only authorized personnel can access presentation systems. The vulnerability demonstrates the importance of proper authentication mechanisms and input validation in embedded web applications, particularly those handling sensitive business content.