CVE-2024-20399: Cisco NX-OS Software RCE Vulnerability

CVE-2024-20399 Overview

A vulnerability in the CLI of Cisco NX-OS Software could allow an authenticated user in possession of Administrator credentials to execute arbitrary commands as root on the underlying operating system of an affected device.

This vulnerability results from insufficient validation of arguments passed to specific configuration CLI commands. An attacker could exploit this by including crafted input as an argument of an affected configuration CLI command, allowing them to execute arbitrary commands on the underlying operating system with root privileges. Note: For successful exploitation, an attacker must have Administrator credentials.

Critical Impact
Exploiting this vulnerability allows privilege escalation to execute commands as root, compromising the device's security.

Affected Products

Cisco NX-OS
Cisco Nexus 7000 Series
Cisco Nexus 9000 Series

Discovery Timeline

Not Available - Vulnerability discovered by Not Available
Not Available - Responsible disclosure to Cisco
Not Available - CVE CVE-2024-20399 assigned
Not Available - Cisco releases security patch
2024-07-01 - CVE CVE-2024-20399 published to NVD
2025-10-28 - Last updated in NVD database

Technical Details for CVE-2024-20399

Vulnerability Analysis

The vulnerability lies in insufficient validation of inputs for specific CLI configurations in Cisco NX-OS. Such improper validation allows an attacker to inject crafted inputs, permitting command execution at the system level with administrative privileges.

Root Cause

The root cause is improper input validation within the configuration command interface of Cisco NX-OS, which leads to command injection vulnerabilities.

Attack Vector

An attacker uses local access with Administrator credentials to inject malicious arguments into CLI commands, exploiting the vulnerability.

bash

# Example exploitation code (Python)
import paramiko

client = paramiko.SSHClient()
client.set_missing_host_key_policy(paramiko.AutoAddPolicy())
client.connect('hostname', username='admin', password='password')

stdin, stdout, stderr = client.exec_command('conf t ; <crafted_input> ; end')

Detection Methods for CVE-2024-20399

Indicators of Compromise

Unexpected system configuration changes
Unauthorized command execution traces
Altered or illegitimate administrative access logs

Detection Strategies

Monitoring for unusual CLI command structures and unauthorized access attempts. Continuous log analysis can help identify suspicious commands and access patterns.

Monitoring Recommendations

Implement real-time monitoring of command logs with anomaly detection to alert on command execution patterns deviating from normal behavior.

How to Mitigate CVE-2024-20399

Immediate Actions Required

Limit CLI access to trusted administrators
Apply Cisco's security patches promptly
Monitor and audit all command-line activities

Patch Information

Refer to Cisco's official advisory here for security updates.

Workarounds

Temporary access restrictions on administrative interfaces and strict IP access controls can reduce exposure to this vulnerability.