CVE-2019-1591 Explained : Impact and Mitigation

A security flaw in Cisco Nexus 9000 Series ACI Mode Switch Software allows a local attacker to escape a restricted shell and execute unauthorized commands with root-level privileges.

Understanding CVE-2019-1591

This CVE involves a vulnerability in a specific CLI command of Cisco Nexus 9000 Series ACI Mode Switch Software.

What is CVE-2019-1591?

The vulnerability allows an authenticated local attacker to break out of a restricted shell on the affected device by exploiting a particular CLI command.

The Impact of CVE-2019-1591

CVSS Base Score: 7.8 (High Severity)
Attack Vector: Local
Attack Complexity: Low
Privileges Required: Low
Confidentiality, Integrity, and Availability Impact: High
Scope: Unchanged
User Interaction: None
The attacker can run unauthorized commands with root-level privileges on vulnerable devices.

Technical Details of CVE-2019-1591

This section provides detailed technical information about the vulnerability.

Vulnerability Description

The flaw arises from inadequate cleansing of user input when using a specific CLI command and its parameters.

Affected Systems and Versions

Product: Cisco NX-OS Software for Nexus 9000 Series Fabric Switches ACI Mode
Vendor: Cisco
Vulnerable Version: 14.0(3d) and earlier

Exploitation Mechanism

An authenticated attacker needs to log in to the device's CLI and execute specific commands to exploit the vulnerability.

Mitigation and Prevention

Protect your systems from this vulnerability by following these steps:

Immediate Steps to Take

Update to a non-vulnerable version (14.0(3d) or later).
Monitor network traffic for signs of exploitation.

Long-Term Security Practices

Implement strong authentication mechanisms.
Regularly review and restrict user privileges.

Patching and Updates

Apply security patches provided by Cisco to address this vulnerability.