CVE-2021-1368 : Security Advisory and Response

A vulnerability in the Unidirectional Link Detection (UDLD) feature of Cisco FXOS Software and Cisco NX-OS Software could allow an unauthenticated, adjacent attacker to execute arbitrary code with administrative privileges or cause a denial of service (DoS) condition on an affected device.

Understanding CVE-2021-1368

This CVE refers to a critical security vulnerability in Cisco FXOS Software and Cisco NX-OS Software that enables attackers to execute malicious code or trigger a DoS attack.

What is CVE-2021-1368?

This vulnerability in the UDLD feature allows attackers, under strict conditions, to send crafted protocol packets and potentially execute code with admin privileges or disrupt service on vulnerable devices.

The Impact of CVE-2021-1368

The severity is high as it can lead to arbitrary code execution or repeated crashing of the UDLD process, resulting in service disruption and device reload. Although the exploit conditions are stringent, successful attacks can have a significant impact.

Technical Details of CVE-2021-1368

This section delves into the vulnerability description, affected systems, versions, and exploitation mechanism.

Vulnerability Description

The insufficient input validation in the UDLD feature allows attackers to send crafted packets to affected devices and gain administrative control or disrupt services.

Affected Systems and Versions

The vulnerable products include Cisco NX-OS Software with specific configurations.

Exploitation Mechanism

Attackers exploit this vulnerability by sending malicious UDLD protocol packets to directly connected devices, potentially executing arbitrary code with admin privileges or causing the UDLD process to crash.

Mitigation and Prevention

Discover immediate steps to take and best practices for long-term security.

Immediate Steps to Take

Disable UDLD on port channels or implement filters to drop crafted packets. Keep systems updated and monitor for unusual activity.

Long-Term Security Practices

Regularly update software and follow security advisories. Implement network segmentation and access control to minimize attack surfaces.

Patching and Updates

Apply patches and updates provided by Cisco to address this vulnerability and enhance system security.