CVE-2023-23774 in MBTS Site Controller
Summary
by MITRE • 08/29/2023
Motorola EBTS/MBTS Site Controller drops to debug prompt on unhandled exception. The Motorola MBTS Site Controller exposes a debug prompt on the device's serial port in case of an unhandled exception. This allows an attacker with physical access that is able to trigger such an exception to extract secret key material and/or gain arbitrary code execution on the device.
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Analysis
by VulDB Data Team • 10/03/2024
The vulnerability identified as CVE-2023-23774 represents a critical security flaw in Motorola's EBTS/MBTS Site Controller systems that fundamentally undermines the device's operational integrity. This issue manifests when the system encounters an unhandled exception, causing it to automatically drop into a debug prompt accessible via the device's serial port interface. The vulnerability specifically affects Motorola's mobile base transceiver site controllers, which serve as critical components in cellular network infrastructure, particularly within 2G and 3G networks. These controllers manage radio frequency operations and maintain communication between mobile devices and the core network, making them prime targets for attackers seeking to compromise cellular infrastructure. The flaw stems from inadequate exception handling mechanisms within the device's firmware, where the system fails to properly manage error conditions that should be gracefully handled rather than resulting in debug interface exposure.
The technical exploitation of this vulnerability requires an attacker to possess physical access to the device and the ability to trigger an unhandled exception condition, which can be accomplished through various means including sending malformed data packets or manipulating system parameters. When the exception occurs, the debug prompt becomes accessible through the serial port, providing direct access to the device's underlying system without proper authentication mechanisms. This exposure creates a direct pathway for attackers to extract sensitive cryptographic key material that is typically stored in memory or configuration files, potentially enabling them to decrypt communications, impersonate legitimate network equipment, or gain full administrative control over the affected site controller. The debug interface provides access to system commands and memory locations that would normally be restricted, allowing for arbitrary code execution capabilities that could enable persistent backdoor installation or further network infiltration.
The operational impact of this vulnerability extends far beyond the immediate device compromise, as it fundamentally threatens the security and integrity of cellular networks that rely on these controllers for their operation. Network operators using affected Motorola MBTS Site Controllers face potential exposure to sophisticated attacks that could disrupt service availability, enable eavesdropping on mobile communications, or provide attackers with entry points to broader network infrastructure. The vulnerability is particularly concerning because it operates at the physical layer of security, requiring only physical access rather than sophisticated network-based attacks, making it accessible to attackers with relatively limited technical resources. This flaw can be exploited to gain unauthorized access to critical network infrastructure components, potentially enabling large-scale service disruption or surveillance capabilities that could affect thousands of mobile users simultaneously.
Organizations should implement immediate mitigation strategies including physical security enhancements to restrict access to affected devices, disabling unused serial ports where possible, and implementing proper exception handling procedures through firmware updates. The vulnerability aligns with CWE-248, which addresses "Uncaught Exception," and represents a classic example of poor error handling in embedded systems that exposes debugging interfaces during error conditions. From an attack perspective, this vulnerability maps to several ATT&CK techniques including T1059 for command and scripting interpreter usage, T1078 for valid accounts, and T1566 for phishing, as attackers may use physical access or social engineering to gain initial device access. Network administrators should conduct comprehensive inventory assessments to identify all affected Motorola devices, implement robust physical security controls including locked enclosures and access logs, and establish monitoring procedures to detect unauthorized serial port access attempts. Regular firmware updates and security patches should be prioritized to address this vulnerability, while incident response procedures should include specific protocols for handling potential exploitation of this flaw in cellular network environments.