CVE-2019-3939 in AM-100
Summary
by MITRE
Crestron AM-100 with firmware 1.6.0.2 and AM-101 with firmware 2.7.0.2 use default credentials admin/admin and moderator/moderator for the web interface. An unauthenticated, remote attacker can use these credentials to gain privileged access to the device.
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Analysis
by VulDB Data Team • 09/11/2023
The Crestron AM-100 and AM-101 devices represent networked automation controllers commonly deployed in enterprise environments for managing building systems and IoT infrastructure. These devices operate with web-based management interfaces that facilitate configuration and monitoring of critical automation functions. The vulnerability stems from the implementation of default authentication credentials that remain unchanged following device deployment, creating a persistent security weakness that adversaries can exploit without requiring any specialized tools or prior access to the network. The specific default credentials admin/admin and moderator/moderator are hardcoded into the firmware and provide administrative privileges to anyone who can access the web interface.
This vulnerability represents a critical security flaw that maps directly to CWE-798, which addresses the use of hard-coded credentials in software implementations. The flaw exists at the authentication layer where the system fails to enforce proper credential management practices, allowing for unauthorized remote access to privileged administrative functions. The attack vector is particularly concerning as it requires no authentication or network reconnaissance, making it accessible to any attacker with knowledge of the default credentials. The web interface exposure creates an attack surface that can be leveraged by threat actors to gain complete control over the automation systems, potentially affecting building security, environmental controls, and other critical infrastructure components.
The operational impact of this vulnerability extends beyond simple unauthorized access to encompass potential disruption of critical building automation systems and compromise of sensitive environmental data. An attacker with administrative access could modify system configurations, disable security features, or manipulate environmental controls to create physical security risks. The remote nature of the attack means that adversaries do not require physical access to the devices or network proximity, making the vulnerability particularly dangerous in enterprise environments where such devices may be exposed to external network traffic. The presence of these default credentials also enables lateral movement within networks, as attackers can use compromised devices as stepping stones to access other systems within the enterprise infrastructure.
Organizations should immediately implement remediation measures including changing default credentials to strong, unique passwords for all affected devices. Network segmentation should be implemented to isolate these devices from critical network segments, and access controls should be configured to limit web interface access to authorized personnel only. The vulnerability also highlights the importance of regular firmware updates and security audits to identify and remediate similar issues. According to ATT&CK framework, this vulnerability maps to T1078 for valid accounts and T1046 for network service scanning, as attackers can leverage the default credentials to establish persistent access and potentially discover additional vulnerable systems. Device manufacturers should implement mandatory credential change procedures during initial setup and disable default accounts by default to prevent similar vulnerabilities in future deployments.