CVE-2019-3926 in AM-100
Summary
by MITRE
Crestron AM-100 with firmware 1.6.0.2 and AM-101 with firmware 2.7.0.2 are vulnerable to command injection via SNMP OID iso.3.6.1.4.1.3212.100.3.2.14.1. A remote, unauthenticated attacker can use this vulnerability to execute operating system commands as root.
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Analysis
by VulDB Data Team • 09/11/2023
The vulnerability identified in CVE-2019-3926 affects Crestron AM-100 and AM-101 network infrastructure devices running specific firmware versions, presenting a critical command injection flaw that can be exploited remotely without authentication. This vulnerability resides within the Simple Network Management Protocol implementation of these devices, specifically targeting the SNMP Object Identifier iso.3.6.1.4.1.3212.100.3.2.14.1 which controls system command execution functions. The flaw represents a severe security weakness that allows attackers to escalate privileges and execute arbitrary operating system commands with root-level access, effectively compromising the entire device and potentially the network it operates within.
The technical exploitation of this vulnerability stems from improper input validation within the SNMP OID handling mechanism of the affected Crestron devices. When the system processes commands through this specific OID, it fails to properly sanitize user-supplied data, creating an injection point where attacker-controlled commands can be passed directly to the underlying operating system shell. This type of vulnerability maps directly to CWE-77 Command Injection, which is classified as a high-severity weakness in the Common Weakness Enumeration catalog. The vulnerability exists in the device's network management interface where SNMP queries are processed, making it accessible to any remote attacker who can send SNMP packets to the device's management interface.
The operational impact of this vulnerability extends beyond simple device compromise, as it provides attackers with complete administrative control over the affected systems. With root-level execution capabilities, an attacker can modify device configurations, install malicious software, access sensitive data, and potentially use the compromised device as a pivot point to attack other systems within the network. The remote and unauthenticated nature of the exploit means that attackers do not need any credentials or physical access to the device to leverage this vulnerability, making it particularly dangerous in enterprise environments where such devices often serve as critical infrastructure components. This vulnerability directly aligns with ATT&CK technique T1059.001 Command and Scripting Interpreter for Windows Command Shell, as it enables the execution of operating system commands through the device's management interface.
Organizations affected by this vulnerability should immediately implement network segmentation to isolate these devices from critical network segments and apply firmware updates from Crestron to address the command injection flaw. Network monitoring should be enhanced to detect unusual SNMP traffic patterns that might indicate exploitation attempts, and access controls should be implemented to restrict SNMP access to trusted management systems only. The vulnerability demonstrates the importance of proper input validation in network management protocols and highlights the need for regular security assessments of network infrastructure devices. Additionally, implementing network access control lists and disabling unnecessary SNMP services where possible can significantly reduce the attack surface and prevent exploitation of similar vulnerabilities in the future.