CVE-2016-1329 in NX-OS
Summary
by MITRE
Cisco NX-OS 6.0(2)U6(1) through 6.0(2)U6(5) on Nexus 3000 devices and 6.0(2)A6(1) through 6.0(2)A6(5) and 6.0(2)A7(1) on Nexus 3500 devices has hardcoded credentials, which allows remote attackers to obtain root privileges via a (1) TELNET or (2) SSH session, aka Bug ID CSCuy25800.
If you want to get best quality of vulnerability data, you may have to visit VulDB.
Analysis
by VulDB Data Team • 07/08/2022
The vulnerability identified as CVE-2016-1329 represents a critical security flaw in Cisco NX-OS software versions affecting Nexus 3000 and 3500 series switches. This issue stems from the presence of hardcoded credentials within the network device firmware, creating a persistent backdoor that can be exploited by remote attackers to gain unauthorized administrative access. The affected software versions include specific release trains such as 6.0(2)U6(1) through 6.0(2)U6(5) for Nexus 3000 devices and 6.0(2)A6(1) through 6.0(2)A6(5) and 6.0(2)A7(1) for Nexus 3500 devices, indicating that this flaw was present across multiple software releases and affected a significant portion of Cisco's data center switching infrastructure.
The technical implementation of this vulnerability involves the inclusion of hardcoded username and password combinations within the NX-OS software binary, which are not configurable or removable by administrators. When attackers establish either TELNET or SSH connections to affected devices, they can leverage these predetermined credentials to authenticate as root users without requiring legitimate authentication mechanisms. This approach bypasses all standard security controls including password policies, account lockout mechanisms, and multi-factor authentication systems. The vulnerability operates at the operating system level within the NX-OS environment, making it particularly dangerous as it provides complete administrative control over the network switch functionality and can be exploited without any prior knowledge of legitimate user credentials or network topology.
The operational impact of this vulnerability extends far beyond simple unauthorized access, as it provides attackers with complete root privileges that enable them to modify network configurations, implement malicious network policies, and potentially establish persistent backdoors within the network infrastructure. This vulnerability directly violates fundamental security principles including the principle of least privilege and authentication integrity, as defined in the CWE (Common Weakness Enumeration) catalog under weakness category CWE-798. The attack surface is particularly concerning given that the vulnerability affects data center switching equipment that typically operates in highly sensitive network environments where these devices serve as critical infrastructure components for enterprise and service provider networks.
The exploitation of this vulnerability can be accomplished remotely without requiring physical access to the devices, making it particularly dangerous in environments where network devices are exposed to untrusted networks or where network segmentation is inadequate. Attackers can leverage this flaw to perform reconnaissance activities, establish command and control channels, or conduct lateral movement attacks within the network. The vulnerability's classification under the ATT&CK framework would place it within the credential access and privilege escalation domains, specifically mapping to techniques such as valid accounts and legitimate credentials. Organizations affected by this vulnerability face significant risks including data breaches, network disruption, and potential compromise of entire network segments that depend on these core switching devices for connectivity and security policy enforcement.
Mitigation strategies for this vulnerability require immediate software updates to the latest available NX-OS releases that address the hardcoded credential issue, along with comprehensive network security monitoring to detect any potential exploitation attempts. Administrators should implement network segmentation to limit the attack surface, disable unnecessary services such as TELNET where SSH is available, and establish robust monitoring for authentication events. The vulnerability demonstrates the critical importance of secure software development practices and the necessity of regular security assessments to identify and remediate hardcoded credentials in network infrastructure devices. Organizations should also consider implementing network access control lists, intrusion detection systems, and regular vulnerability scanning to identify similar issues that may exist in other network equipment and software components within their infrastructure.