CVE-2017-12339 : Exploit Details and Defense Strategies

A weakness has been identified in Cisco NX-OS System Software's Command Line Interface (CLI) that could potentially be exploited by an authenticated local attacker to execute a command injection attack.

Understanding CVE-2017-12339

What is CVE-2017-12339?

A vulnerability in the CLI of Cisco NX-OS System Software allows an authenticated local attacker to perform a command injection attack due to insufficient input validation of command arguments.

The Impact of CVE-2017-12339

The successful exploitation of this vulnerability could grant the attacker the ability to execute unauthorized commands at the user's privilege level, potentially compromising the system's security.

Technical Details of CVE-2017-12339

Vulnerability Description

Inadequate validation of command arguments in the CLI parser
Allows an attacker to inject crafted command arguments into a vulnerable CLI command
Impacts various products running on Cisco NX-OS System Software

Affected Systems and Versions

Multilayer Director Switches
Nexus 2000 Series Fabric Extenders
Nexus 3000 Series Switches
Nexus 5000 Series Switches
Nexus 5500 Platform Switches
Nexus 5600 Platform Switches
Nexus 6000 Series Switches
Nexus 7000 Series Switches
Nexus 7700 Series Switches
Nexus 9000 Series Fabric Switches in ACI mode
Nexus 9000 Series Switches in standalone NX-OS mode
Nexus 9500 R-Series Line Cards and Fabric Modules

Exploitation Mechanism

Attacker injects specifically crafted command arguments into a vulnerable CLI command
Can execute commands outside the user's environment at the user's privilege level

Mitigation and Prevention

Immediate Steps to Take

Apply vendor patches and updates promptly
Monitor network traffic for any signs of exploitation
Restrict access to vulnerable systems

Long-Term Security Practices

Regular security training for staff on identifying and reporting suspicious activities
Implement strong password policies and multi-factor authentication
Conduct regular security audits and vulnerability assessments

Patching and Updates

Cisco has released patches to address this vulnerability
Ensure all affected systems are updated with the latest security fixes