CVE-2020-3165 : What You Need to Know

A vulnerability in the implementation of Border Gateway Protocol (BGP) Message Digest 5 (MD5) authentication in Cisco NX-OS Software could allow an unauthenticated, remote attacker to bypass MD5 authentication and establish a BGP connection with the device.

Understanding CVE-2020-3165

This CVE involves a security flaw in Cisco NX-OS Software that enables an attacker to bypass MD5 authentication in BGP, potentially leading to unauthorized BGP connections.

What is CVE-2020-3165?

The vulnerability allows an attacker to establish a BGP session with the NX-OS device without MD5 authentication by exploiting a flaw in the BGP MD5 authentication implementation.

The Impact of CVE-2020-3165

CVSS Base Score: 8.2 (High Severity)
Attack Vector: Network
Integrity Impact: High
Confidentiality Impact: Low
The vulnerability could result in unauthorized access to BGP sessions, compromising network integrity.

Technical Details of CVE-2020-3165

The technical aspects of the vulnerability are as follows:

Vulnerability Description

The flaw allows an unauthenticated attacker to bypass MD5 authentication in BGP.

Affected Systems and Versions

Affected Product: Cisco NX-OS Software
Affected Version: 9.2(1)

Exploitation Mechanism

The vulnerability is exploited by sending malicious packets over a TCP connection that appears to come from a trusted BGP peer.

Mitigation and Prevention

Steps to address and prevent exploitation of the vulnerability:

Immediate Steps to Take

Configure MD5 authentication for BGP sessions.
Implement access control lists to restrict BGP traffic.

Long-Term Security Practices

Regularly monitor BGP sessions for unauthorized connections.
Keep software and security configurations up to date.

Patching and Updates

Apply patches and updates provided by Cisco to address the vulnerability.