CVE-2019-1778 in NX-OS
Summary
by MITRE
A vulnerability in the CLI of Cisco NX-OS Software could allow an authenticated, local attacker to execute arbitrary commands on the underlying Linux operating system with the privilege level of root. The vulnerability is due to insufficient validation of arguments passed to a specific CLI command on the affected device. An attacker could exploit this vulnerability by including malicious input as the argument of an affected command. A successful exploit could allow the attacker to execute arbitrary commands on the underlying Linux operating system with elevated privileges. An attacker would need valid administrator credentials to exploit this vulnerability.
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Analysis
by VulDB Data Team • 09/21/2023
The vulnerability identified as CVE-2019-1778 represents a critical command injection flaw within Cisco NX-OS Software that undermines the security boundaries of network infrastructure devices. This vulnerability specifically affects the command line interface implementation where insufficient input validation creates an attack surface for authenticated local adversaries to escalate privileges and execute arbitrary code at the root level of the underlying Linux operating system. The flaw exists in the manner in which the software processes arguments passed to specific CLI commands, failing to properly sanitize or validate user-supplied inputs before processing them within the system's execution context. This type of vulnerability falls under the CWE-77 category of command injection, where user-controllable data is directly incorporated into system commands without adequate sanitization measures. The attack vector requires local access with administrator credentials, making it a privilege escalation vulnerability rather than a remote exploit, though the impact remains severe given the elevated privileges that can be gained.
The operational impact of this vulnerability extends beyond simple privilege escalation to potentially compromise the entire network infrastructure platform. When exploited successfully, an authenticated attacker can execute arbitrary commands with root privileges, effectively bypassing all security controls that rely on the integrity of the CLI interface. This capability allows for complete system compromise including but not limited to data exfiltration, modification of network configurations, installation of backdoors, and establishment of persistent access points within the network environment. The vulnerability affects Cisco Nexus series switches running NX-OS software versions prior to the patched releases, making it particularly concerning for enterprise networks where these devices form critical components of the network fabric. The attack scenario typically involves an attacker who has already established administrative access to the device through legitimate means, then leveraging this access to exploit the command injection vulnerability and gain unauthorized root-level access to the underlying Linux operating system.
Security professionals should understand that this vulnerability aligns with ATT&CK technique T1059.001 for command and scripting interpreter, specifically focusing on the execution of commands through the command line interface. The vulnerability demonstrates how legitimate administrative interfaces can be weaponized when proper input validation is absent, creating a pathway for attackers to perform malicious activities that would otherwise be restricted by normal security controls. Organizations must implement comprehensive monitoring and detection capabilities to identify suspicious command execution patterns, particularly when administrative accounts are involved in unusual or unexpected CLI activities. The vulnerability also highlights the importance of principle of least privilege implementation, where even administrative accounts should be subject to additional security controls and monitoring. Mitigation strategies should include immediate patch deployment for affected Cisco NX-OS software versions, implementation of strict input validation controls at the CLI level, and enhanced monitoring of administrative sessions for anomalous command patterns. Network segmentation and access control measures should be reinforced to limit the potential impact of successful exploitation, while regular security assessments should be conducted to identify similar validation weaknesses in other network management interfaces and command processing systems.