CVE-2019-1596 Explained : Impact and Mitigation

A flaw in the Bash shell implementation for Cisco NX-OS Software could allow a local attacker to elevate their privilege level to root. This vulnerability affects various Cisco Nexus switches.

Understanding CVE-2019-1596

This CVE identifies a privilege escalation vulnerability in Cisco NX-OS Software due to incorrect permissions on a system executable.

What is CVE-2019-1596?

The vulnerability allows a local attacker with valid credentials to execute specially crafted commands at the Bash prompt, leading to privilege escalation to root level.

The Impact of CVE-2019-1596

CVSS Base Score: 7.8 (High Severity)
Attack Vector: Local
Attack Complexity: Low
Privileges Required: Low
Confidentiality, Integrity, and Availability Impact: High

Technical Details of CVE-2019-1596

This section provides detailed technical information about the vulnerability.

Vulnerability Description

The vulnerability arises from incorrect permissions on a system executable, allowing an authenticated attacker to escalate privileges to root.

Affected Systems and Versions

The following Cisco devices are affected:

Nexus 3000 Series Switches (versions prior to 7.0(3)I7(4))
Nexus 3500 Platform Switches (versions prior to 7.0(3)I7(4))
Nexus 3600 Platform Switches (versions prior to 7.0(3)F3(5))
Nexus 9000 Series Switches in Standalone NX-OS Mode (versions prior to 7.0(3)I7(4))
Nexus 9500 R-Series Line Cards and Fabric Modules (versions prior to 7.0(3)F3(5))

Exploitation Mechanism

The attacker needs valid user credentials to exploit the vulnerability by entering crafted commands at the Bash prompt.

Mitigation and Prevention

Protect your systems from CVE-2019-1596 with the following steps:

Immediate Steps to Take

Apply vendor patches promptly
Monitor for any unauthorized access attempts

Long-Term Security Practices

Implement the principle of least privilege
Regularly review and update system permissions

Patching and Updates

Ensure timely installation of security patches provided by Cisco to address this vulnerability.