CVE-2015-6020 in PMG5318-B20A
Summary
by MITRE
ZyXEL PMG5318-B20A devices with firmware 1.00AANC0b5 allow remote authenticated users to obtain administrative privileges by leveraging access to the user account.
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Analysis
by VulDB Data Team • 11/09/2024
The ZyXEL PMG5318-B20A router represents a significant security vulnerability classified as CVE-2015-6020, where authenticated users can escalate their privileges to administrative level through flawed access control mechanisms. This vulnerability specifically affects devices running firmware version 1.00AANC0b5 and demonstrates a critical flaw in the device's privilege management system that allows lateral movement within the network infrastructure. The issue stems from improper validation of user permissions and roles within the router's web-based management interface, creating an avenue for privilege escalation attacks that can compromise the entire network.
The technical flaw manifests through a weakness in the authentication and authorization framework where legitimate user accounts can be exploited to gain elevated privileges without proper verification mechanisms. This vulnerability operates under the Common Weakness Enumeration category CWE-284 which specifically addresses improper access control, and aligns with ATT&CK technique T1078 for valid accounts and privilege escalation. The flaw allows attackers who have already established a user-level session to manipulate the system's permission structure and assume administrative control over the device, effectively bypassing the intended security boundaries.
The operational impact of this vulnerability extends beyond simple privilege escalation, as it provides attackers with complete administrative control over the affected router, enabling them to modify network configurations, implement man-in-the-middle attacks, redirect traffic, and potentially establish persistent access points within the network infrastructure. Network administrators lose visibility into their own network security posture as the compromised device can be used to hide malicious activities or serve as a pivot point for further attacks against internal network segments. This vulnerability particularly affects enterprise and home network environments where such devices serve as primary network gateways and security perimeters.
Mitigation strategies for CVE-2015-6020 should prioritize immediate firmware updates from ZyXEL to address the privilege escalation flaw, while network administrators should implement strict network segmentation to limit the blast radius of potential compromise. Additional protective measures include disabling unnecessary administrative interfaces, implementing strong access controls with multi-factor authentication, and conducting regular security audits of network infrastructure devices. Organizations should also establish monitoring protocols to detect unauthorized privilege changes and maintain up-to-date vulnerability assessments to identify similar weaknesses in other network equipment. The vulnerability underscores the importance of proper privilege separation and access control validation within network infrastructure devices, particularly those with web-based management interfaces that are frequently targeted by attackers seeking to establish persistent network footholds.