CVE-2019-3936 in AM-100
Summary
by MITRE
Crestron AM-100 with firmware 1.6.0.2 and AM-101 with firmware 2.7.0.2 is vulnerable to denial of service via a crafted request to TCP port 389. The request will force the slideshow to transition into a "stopped" state. A remote, unauthenticated attacker can use this vulnerability to stop an active slideshow.
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Analysis
by VulDB Data Team • 09/11/2023
The CVE-2019-3936 vulnerability affects Crestron AM-100 and AM-101 devices running specific firmware versions, presenting a significant denial of service risk in automated presentation systems. These devices are commonly deployed in corporate boardrooms, conference centers, and educational institutions where reliable presentation functionality is critical for business operations. The vulnerability manifests through a crafted request sent to TCP port 389, which is typically associated with the Lightweight Directory Access Protocol ldap service. This targeting of port 389 suggests the vulnerability may be related to improper input validation or state management within the device's network handling mechanisms.
The technical flaw in these Crestron devices stems from inadequate validation of incoming network requests that can manipulate the slideshow functionality. When a maliciously crafted request is received on the designated port, the system fails to properly handle the malformed data, causing the slideshow to transition into an unintended "stopped" state. This behavior represents a classic state manipulation vulnerability where external inputs can directly control internal device operations without proper authentication or authorization checks. The vulnerability's classification aligns with CWE-20, which covers "Improper Input Validation," and CWE-362, addressing "Concurrent Execution using Shared Resource with Improper Synchronization." The device's failure to properly validate request parameters and maintain secure state transitions creates an exploitable condition that allows arbitrary control over presentation functionality.
The operational impact of this vulnerability extends beyond simple service disruption, potentially causing significant business interruptions in environments where uninterrupted presentations are essential. Remote attackers can exploit this vulnerability without requiring authentication credentials, making it particularly dangerous as it can be leveraged from any network position. The ability to stop active slideshows during critical presentations can result in lost productivity, damaged professional relationships, and potential financial losses. In high-security environments, this vulnerability could also indicate broader system compromise potential, as it demonstrates the device's susceptibility to unauthorized manipulation of critical presentation functions. The attack vector's simplicity and the lack of authentication requirements make this vulnerability particularly attractive to threat actors seeking to disrupt business operations.
Organizations utilizing affected Crestron devices should implement immediate mitigations to protect against this vulnerability. Network segmentation and firewall rules should be configured to restrict access to TCP port 389 on these devices, particularly when the port is not required for legitimate operations. The most effective long-term solution involves updating the firmware to versions that address the input validation flaws and properly handle malformed requests. Security teams should also consider implementing network monitoring to detect unusual patterns of requests targeting these specific ports. The vulnerability's characteristics align with ATT&CK technique T1499.002, "Endpoint Denial of Service," and T1566.002, "Phishing via Social Engineering," as attackers may use social engineering to gain initial access before exploiting this denial of service condition. Regular vulnerability assessments and network scanning should be conducted to identify any other potentially affected devices within the organization's infrastructure, as similar vulnerabilities may exist in other networked presentation systems or embedded devices.