CVE-2019-1602 in NX-OS
Summary
by MITRE
A vulnerability in the filesystem permissions of Cisco NX-OS Software could allow an authenticated, local attacker to access sensitive data that could be used to elevate their privileges to administrator. The vulnerability is due to improper implementation of filesystem permissions. An attacker could exploit this vulnerability by logging in to the CLI of an affected device, accessing a specific file, and leveraging this information to authenticate to the NX-API server. A successful exploit could allow an attacker to make configuration changes as administrator. Note: NX-API is disabled by default. Nexus 3000 Series Switches are affected in versions prior to 7.0(3)I7(4). Nexus 3500 Platform Switches are affected in versions prior to 7.0(3)I7(4). Nexus 3600 Platform Switches are affected in versions prior to 7.0(3)F3(5). Nexus 9000 Series Switches-Standalone are affected in versions prior to 7.0(3)I7(4). Nexus 9500 R-Series Line Cards and Fabric Modules are affected in versions prior to 7.0(3)F3(5).
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Analysis
by VulDB Data Team • 07/31/2023
This vulnerability resides within the filesystem permission implementation of Cisco NX-OS Software, representing a critical privilege escalation flaw that undermines the security posture of network infrastructure devices. The issue stems from improper access controls that fail to adequately enforce filesystem boundaries, creating a pathway for authenticated local attackers to access sensitive system files. The vulnerability specifically affects multiple Nexus series switches including 3000, 3500, 3600, and 9000 series platforms, with affected versions prior to the specified release numbers. The flaw demonstrates characteristics consistent with CWE-276, which addresses improper file permissions, and aligns with ATT&CK technique T1068, involving local privilege escalation through system weaknesses. The vulnerability exploits the fundamental principle of least privilege by allowing unauthorized access to system resources that should remain restricted to administrative users.
The exploitation process begins with an authenticated local attacker gaining access to the command-line interface of the affected device, a prerequisite that reduces the attack surface but still represents a significant security gap. Once inside the system, the attacker can access specific files containing sensitive authentication information or configuration data that would normally be protected by proper filesystem permissions. The vulnerability's impact extends beyond simple data access, as the compromised information can be leveraged to authenticate to the NX-API server, which serves as a critical management interface for network configuration. This authentication bypass capability transforms a local access violation into a potential full administrative compromise, enabling attackers to make arbitrary configuration changes that could severely impact network operations. The NX-API functionality, while disabled by default according to the vulnerability description, represents a critical attack vector when enabled, as it provides programmatic access to device management functions.
The operational impact of this vulnerability extends beyond immediate privilege escalation to encompass potential network disruption, data compromise, and unauthorized configuration changes. Attackers could exploit this vulnerability to modify routing configurations, alter access control lists, disable security features, or establish persistent access points within the network infrastructure. The affected hardware platforms represent core network switching equipment that typically operates in critical network segments, making the potential impact substantial. Organizations running vulnerable versions of NX-OS software face the risk of unauthorized network modifications that could lead to service disruption, data exfiltration, or further lateral movement within the network environment. The vulnerability's presence in multiple Nexus platform lines indicates a widespread issue affecting Cisco's core switching product portfolio, potentially exposing organizations to coordinated attacks across their network infrastructure.
Mitigation strategies should focus on immediate remediation through firmware updates to the patched versions specified in the vulnerability advisory, with particular attention to the affected Nexus 3000, 3500, 3600, and 9000 series platforms. Network administrators should also implement additional security controls including disabling NX-API if not required, enforcing strict access controls for CLI access, and monitoring for unauthorized access attempts. The vulnerability highlights the importance of proper filesystem permission management and demonstrates the critical need for regular security assessments of network infrastructure components. Organizations should consider implementing network segmentation to limit the potential impact of successful exploitation and establish robust monitoring procedures to detect anomalous configuration changes that might indicate compromise. This vulnerability serves as a reminder of the critical importance of maintaining current security patches and the potential consequences of inadequate permission controls in network infrastructure software.