CVE-2017-8156 in B2338-168
Summary
by MITRE
The outdoor unit of Customer Premise Equipment (CPE) product B2338-168 V100R001C00 has a no authentication vulnerability on the serial port. An attacker can access the serial port on the circuit board of the outdoor unit and log in to the CPE without authentication. Successful exploit could allow the attacker to take control over the outdoor unit.
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Analysis
by VulDB Data Team • 01/11/2023
The vulnerability identified as CVE-2017-8156 affects the B2338-168 V100R001C00 Customer Premise Equipment product, specifically targeting the outdoor unit's serial port interface. This represents a critical security flaw that undermines the fundamental security posture of network infrastructure equipment deployed in customer environments. The vulnerability resides in the lack of authentication mechanisms for accessing the serial port, which serves as a direct pathway to system-level access and control over the affected hardware components.
The technical implementation of this vulnerability stems from insufficient access control measures at the hardware level of the CPE device. Serial ports typically serve as administrative interfaces for device configuration, diagnostics, and system management purposes, yet in this case, the device fails to enforce any form of authentication before granting access to these critical interfaces. This absence of authentication aligns with CWE-305 weakness category, which specifically addresses authentication failures that can lead to unauthorized access to system resources. The vulnerability creates a direct attack surface that allows malicious actors to bypass normal authentication procedures and gain immediate administrative access to the outdoor unit's operating system and firmware components.
From an operational perspective, successful exploitation of this vulnerability presents significant risks to network security and infrastructure integrity. An attacker who gains access to the unauthenticated serial port can execute arbitrary commands, modify system configurations, install malicious software, and potentially establish persistent access to the compromised device. The outdoor unit serves as a critical component in network connectivity and often operates in physically accessible locations, making the attack surface even more concerning. This vulnerability directly impacts the principle of least privilege and can lead to complete system compromise, allowing attackers to manipulate network traffic, disable security features, or use the device as a pivot point for attacking other network segments.
The security implications extend beyond immediate system compromise to encompass broader network infrastructure risks. Attackers can leverage this vulnerability to conduct reconnaissance activities, establish backdoors, or use the compromised unit as a staging point for further attacks against internal networks. This scenario aligns with ATT&CK technique T1059 which covers command and scripting interpreter usage, and T1068 which addresses local privilege escalation. The vulnerability also represents a failure in defense in depth principles, as multiple security layers should have been implemented to protect against unauthorized physical access to critical system interfaces. Organizations should consider implementing physical security controls, network segmentation, and regular security assessments to address similar vulnerabilities in their infrastructure.
Mitigation strategies should include immediate firmware updates from the vendor to address the authentication gap, implementation of physical access controls to prevent unauthorized individuals from accessing the serial ports, and network-level restrictions that limit access to administrative interfaces. Additionally, organizations should establish monitoring procedures to detect unauthorized access attempts and implement regular security audits to identify similar vulnerabilities in other network equipment. The vulnerability underscores the importance of secure device design practices and the need for comprehensive security testing throughout the product development lifecycle to prevent such critical authentication failures from reaching production environments.