CVE-2017-16241 in Symmetry Door Edge Network Controller
Summary
by MITRE
Incorrect access control in AMAG Symmetry Door Edge Network Controllers (EN-1DBC Boot App 23611 03.60 and STD App 23603 03.60; EN-2DBC Boot App 24451 01.00 and STD App 2461 01.00) enables remote attackers to execute door controller commands (e.g., lock, unlock, add ID card value) by sending unauthenticated requests to the affected devices via Serial over TCP/IP, as demonstrated by a Ud command.
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Analysis
by VulDB Data Team • 12/13/2019
The vulnerability identified as CVE-2017-16241 represents a critical access control flaw within AMAG Symmetry Door Edge Network Controllers, specifically affecting firmware versions EN-1DBC Boot App 23611 03.60 and STD App 23603 03.60, as well as EN-2DBC Boot App 24451 01.00 and STD App 2461 01.00. This weakness resides in the authentication mechanisms governing serial over tcp/ip communication channels, creating a pathway for unauthorized remote execution of privileged door control operations. The flaw manifests through the exploitation of a command interface that accepts unauthenticated requests, allowing malicious actors to issue commands such as lock, unlock, and add ID card values without proper authorization. This vulnerability directly maps to CWE-284, which describes improper access control, and falls under the broader category of weak authentication mechanisms in networked security systems. The attack vector specifically leverages the Serial over TCP/IP protocol, which is commonly used for device management and configuration in industrial control systems and access control environments.
The operational impact of this vulnerability extends beyond simple unauthorized access, as it enables attackers to manipulate physical security systems in real-time. An attacker who successfully exploits this flaw can execute commands that fundamentally alter the security posture of the affected facilities, potentially allowing unauthorized individuals to gain physical access to restricted areas. The demonstration of the vulnerability using the Ud command shows that the system accepts and processes user data commands without verifying the authenticity of the requesting entity. This capability allows for the addition of new ID card values, which can be used to grant access rights to previously unauthorized individuals, effectively compromising the entire access control infrastructure. The implications are particularly severe in environments where physical security is paramount, such as government facilities, data centers, or corporate headquarters where unauthorized access could result in significant financial loss, data breaches, or safety risks. The vulnerability affects the fundamental integrity of the access control system, potentially allowing attackers to maintain persistent access or cause denial of service conditions by locking or unlocking doors at will.
Mitigation strategies for this vulnerability require immediate implementation of network segmentation and access controls to prevent unauthorized network access to the affected door controllers. Organizations should implement strict firewall rules that restrict access to the Serial over TCP/IP ports to only authorized management systems and personnel. Network monitoring should be enhanced to detect unusual command patterns or unauthorized access attempts to the door controller interfaces. The affected devices should be updated with firmware patches provided by AMAG to address the authentication bypass issue, and all system administrators should be educated about the importance of securing physical access control systems. Additionally, implementing multi-factor authentication for administrative access and regular security audits of access control systems can help prevent exploitation of similar vulnerabilities. This vulnerability aligns with ATT&CK technique T1071.004, which covers application layer protocol traffic shaping, and T1190, which addresses exploit for client execution, highlighting the need for comprehensive network security measures. The remediation process should include thorough vulnerability assessments of all similar access control devices within the network infrastructure to identify potential additional exposure points that may present similar access control weaknesses.