CVE-2021-1231 Explained : Impact and Mitigation

A vulnerability in the Link Layer Discovery Protocol (LLDP) for Nexus 9000 Series Fabric Switches in Application Centric Infrastructure (ACI) mode could allow an unauthenticated, adjacent attacker to disable switching on a small form-factor pluggable (SFP) interface. This could disrupt network traffic.

Understanding CVE-2021-1231

This CVE describes a denial of service vulnerability affecting Cisco Nexus 9000 Series Fabric Switches in ACI mode.

What is CVE-2021-1231?

The vulnerability in LLDP could be exploited by an adjacent attacker to disrupt network traffic by disabling switching on an SFP interface.

The Impact of CVE-2021-1231

If successfully exploited, this vulnerability could lead to a denial of service situation, impacting the availability of network services.

Technical Details of CVE-2021-1231

This section provides detailed technical insights into the vulnerability.

Vulnerability Description

The vulnerability stems from incomplete validation of the LLDP packet source, allowing attackers to send crafted packets to disable switching on the SFP interface.

Affected Systems and Versions

Cisco NX-OS System Software in ACI Mode is affected by this vulnerability.

Exploitation Mechanism

Attackers can exploit this vulnerability by sending a crafted LLDP packet on an SFP interface to the affected device.

Mitigation and Prevention

To secure systems from CVE-2021-1231, follow these guidelines.

Immediate Steps to Take

Implement network security best practices and monitor for any suspicious LLDP activities.

Long-Term Security Practices

Regularly update and patch affected systems to mitigate the risk of exploitation.

Patching and Updates

Apply relevant patches provided by Cisco to address this vulnerability effectively.