CVE-2019-1790 in NX-OS
Summary
by MITRE
A vulnerability in the CLI of Cisco NX-OS Software could allow an authenticated, local attacker with valid administrator credentials to execute arbitrary commands on the underlying operating system of an affected device. The vulnerability is due to insufficient validation of arguments passed to certain CLI commands. 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 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-2019-1790 represents a critical command injection flaw within Cisco NX-OS Software command line interface implementation. This security weakness resides in the insufficient input validation mechanisms that govern how command line arguments are processed and handled within the network operating system. The vulnerability specifically affects the privileged execution environment where administrative commands are processed, creating a pathway for authenticated attackers to escalate their privileges and gain unauthorized access to the underlying operating system. The flaw demonstrates a classic lack of proper input sanitization and validation that has been documented in numerous security frameworks including CWE-77 and CWE-78, which categorize this as a command injection vulnerability where user-supplied input is directly incorporated into system commands without adequate filtering or escaping mechanisms.
The operational impact of this vulnerability extends beyond simple privilege escalation to encompass full system compromise capabilities. An attacker with valid administrator credentials can exploit this weakness by crafting malicious command arguments that bypass normal input validation checks and directly manipulate the operating system's command execution pipeline. This allows for arbitrary code execution at the system level with the highest possible privileges, potentially enabling attackers to install backdoors, modify system configurations, exfiltrate sensitive data, or establish persistent access to the network infrastructure. The attack vector requires local access with administrative credentials, making it particularly dangerous in environments where administrative access is frequently granted or where credential compromise occurs through social engineering, phishing, or other attack vectors. The vulnerability aligns with ATT&CK technique T1059.001 which describes command and script injection, and specifically targets the operating system command execution components of network devices.
Mitigation strategies for CVE-2019-1790 should prioritize immediate software updates and patches provided by Cisco to address the underlying input validation flaws in the CLI implementation. Organizations must ensure comprehensive network device patch management procedures are in place to prevent exploitation of similar vulnerabilities in the future. Network segmentation and least privilege access controls should be implemented to limit the potential impact of credential compromise, while monitoring solutions should be deployed to detect anomalous command execution patterns that may indicate exploitation attempts. The vulnerability highlights the importance of proper input validation and the principle of least privilege in secure system design, as outlined in security standards such as NIST SP 800-155 and ISO 27001 controls. Regular security assessments and code reviews of command line interfaces should be conducted to identify and remediate similar validation weaknesses before they can be exploited by malicious actors. Additionally, implementing robust logging and audit capabilities for CLI commands will aid in forensic analysis and incident response when such vulnerabilities are successfully exploited.