CVE-2021-1228 : Security Advisory and Response

A vulnerability in the fabric infrastructure VLAN connection establishment of Cisco Nexus 9000 Series Fabric Switches in Application Centric Infrastructure (ACI) Mode could allow an unauthenticated, adjacent attacker to bypass security validations and connect an unauthorized server to the infrastructure VLAN.

Understanding CVE-2021-1228

This CVE identifies a security vulnerability in Cisco Nexus 9000 Series Fabric Switches that could lead to unauthorized access to the infrastructure VLAN.

What is CVE-2021-1228?

The vulnerability allows an unauthenticated attacker to exploit insufficiencies in security requirements during the Link Layer Discovery Protocol (LLDP) setup phase of the infrastructure VLAN.

The Impact of CVE-2021-1228

If successfully exploited, the attacker can connect an unauthorized server to the infrastructure VLAN, gaining privileged access to make unauthorized connections.

Technical Details of CVE-2021-1228

This section covers the specific technical details of the vulnerability.

Vulnerability Description

The vulnerability enables an adjacent attacker to send a crafted LLDP packet to connect an unauthorized server to the infrastructure VLAN.

Affected Systems and Versions

The affected product is "Cisco NX-OS System Software in ACI Mode 11.0(1b)" under vendor Cisco, with no specific affected version mentioned.

Exploitation Mechanism

Exploitation involves sending a crafted LLDP packet on the adjacent subnet to compromise an affected device.

Mitigation and Prevention

To address CVE-2021-1228, immediate action is required in addition to long-term security practices.

Immediate Steps to Take

Immediately restrict network access and review access controls to limit unauthorized connections.

Long-Term Security Practices

Implement VLAN segmentation, regularly monitor network traffic, and conduct security audits to prevent unauthorized access.

Patching and Updates

Apply security patches provided by Cisco to mitigate the vulnerability.