CVE-2019-1795 in NX-OS
Summary
by MITRE
A vulnerability in the CLI of Cisco FXOS Software and 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-2019-1795 represents a critical privilege escalation flaw within the command line interface of Cisco's FXOS and NX-OS software platforms. This weakness resides in the insufficient input validation mechanisms that govern how arguments are processed within specific CLI commands, creating a pathway for authenticated local attackers to bypass normal security controls. The vulnerability affects devices running Cisco FXOS Software and Cisco NX-OS Software where the underlying Linux operating system is present, making it particularly dangerous as it allows attackers to execute commands with root-level privileges. The flaw fundamentally stems from the failure to properly sanitize or validate user input passed to certain CLI commands, enabling attackers to inject malicious payloads that can be interpreted and executed by the underlying operating system.
The technical exploitation of this vulnerability requires an attacker to possess valid administrator credentials, establishing a baseline authentication requirement that limits the attack surface but does not eliminate the risk. Once authenticated, the attacker can leverage the insufficient argument validation by crafting malicious input parameters that are passed to specific CLI commands. This malformed input is then processed by the vulnerable software without adequate sanitization, allowing the execution of arbitrary commands on the underlying Linux system. The vulnerability operates at the interface between the Cisco proprietary CLI implementation and the underlying operating system, where command injection techniques can be employed to escalate privileges and gain complete control over the affected device. This type of flaw falls under the CWE-77 vulnerability class, specifically representing a command injection weakness where user-supplied data is not properly validated or escaped before being executed.
The operational impact of CVE-2019-1795 extends beyond simple privilege escalation, as it provides attackers with complete control over the target device and potentially enables lateral movement within network environments. An attacker with root-level access can modify system configurations, install malicious software, access sensitive data, and establish persistent backdoors. The vulnerability affects network infrastructure devices that are critical to enterprise security, meaning successful exploitation could lead to widespread compromise of network services and data integrity. Organizations running affected Cisco equipment face significant risk as this vulnerability allows attackers to effectively take control of their network infrastructure without requiring external network access or specialized attack tools. The implications for network security are severe, as compromised network devices can serve as entry points for broader attacks against internal systems and can be used to monitor network traffic or disrupt services.
Mitigation strategies for CVE-2019-1795 should prioritize immediate software updates from Cisco, specifically addressing the identified CLI argument validation issues. Organizations must ensure all affected devices receive the relevant security patches and firmware updates provided by Cisco to remediate the vulnerability. Network segmentation and access control measures should be reinforced to limit the potential impact of any successful exploitation attempts, while monitoring systems should be enhanced to detect unusual command execution patterns or unauthorized administrative access. The implementation of least privilege principles should be enforced, ensuring that administrative accounts have only the necessary permissions required for their specific functions. Additionally, regular security audits and vulnerability assessments should be conducted to identify and remediate similar issues within the network infrastructure. This vulnerability demonstrates the importance of proper input validation in security-critical applications and aligns with ATT&CK framework techniques related to privilege escalation and command execution, highlighting the need for comprehensive security controls across all system interfaces.