CVE-2016-10401 in PK5001Z
Summary
by MITRE
ZyXEL PK5001Z devices have zyad5001 as the su password, which makes it easier for remote attackers to obtain root access if a non-root account password is known (or a non-root default account exists within an ISP's deployment of these devices).
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Analysis
by VulDB Data Team • 07/26/2024
The vulnerability identified as CVE-2016-10401 affects ZyXEL PK5001Z broadband router devices, representing a critical authentication flaw that undermines the security posture of network infrastructure deployed by internet service providers. This vulnerability stems from a hardcoded superuser password embedded within the device firmware, specifically the password "zyad5001" which grants administrative privileges to the root account. The flaw creates a significant attack surface where remote adversaries can exploit knowledge of any non-root account password to escalate privileges and gain complete system control. The vulnerability is particularly concerning because it exists in devices deployed within ISP networks, where multiple users may have access to the same infrastructure, creating a cascading security risk that extends beyond individual device boundaries.
The technical implementation of this vulnerability involves a hardcoded credential mechanism that violates fundamental security principles outlined in the CWE-798 weakness category, which addresses the use of hard-coded credentials in software. The presence of a default password that remains unchanged across deployments creates a persistent backdoor that attackers can leverage without requiring complex exploitation techniques. The vulnerability operates at the authentication layer of the device's security architecture, bypassing normal access control mechanisms that should prevent unauthorized administrative access. This flaw directly relates to the ATT&CK technique T1078 which describes legitimate credentials usage, specifically focusing on the exploitation of default accounts and passwords that persist across multiple deployments.
The operational impact of this vulnerability extends far beyond individual device compromise, as it enables attackers to gain persistent access to ISP network infrastructure. When combined with knowledge of any non-root account password, threat actors can escalate privileges and achieve complete control over the affected device, potentially enabling them to modify network configurations, intercept traffic, or establish persistent backdoors. The vulnerability affects the confidentiality, integrity, and availability of the network infrastructure, as attackers can manipulate routing tables, disable security features, or redirect traffic to malicious destinations. The ease of exploitation means that this vulnerability can be leveraged by attackers with minimal technical expertise, making it particularly dangerous in production environments where network reliability and security are paramount.
Organizations should implement immediate mitigation strategies including changing default passwords on all affected devices, disabling unnecessary services, and implementing network segmentation to limit the impact of potential compromise. The recommended approach involves conducting comprehensive inventory audits to identify all affected ZyXEL PK5001Z devices within the network infrastructure, followed by firmware updates if available from the vendor. Network monitoring should be enhanced to detect unusual administrative access patterns, and access controls should be strengthened through the implementation of multi-factor authentication for administrative accounts. The vulnerability demonstrates the critical importance of avoiding hardcoded credentials in embedded systems and highlights the necessity of following security best practices such as those outlined in the NIST Cybersecurity Framework and ISO 27001 standards for secure system design and deployment.