CVE-2019-16023 : Security Advisory and Response

Cisco IOS XR Software BGP EVPN Denial of Service Vulnerabilities

Understanding CVE-2019-16023

This CVE involves weaknesses in Cisco IOS XR Software's implementation of Border Gateway Protocol (BGP) Ethernet VPN (EVPN) functionality, potentially leading to denial of service (DoS) attacks.

What is CVE-2019-16023?

The vulnerabilities stem from incorrect handling of BGP update messages containing manipulated EVPN attributes, allowing unauthenticated remote attackers to trigger abrupt restarts of the BGP process, causing DoS scenarios.

The Impact of CVE-2019-16023

CVSS Base Score: 8.6 (High Severity)
Attack Vector: Network
Availability Impact: High
These vulnerabilities could lead to DoS situations, affecting system availability.

Technical Details of CVE-2019-16023

This section delves into the technical aspects of the vulnerability.

Vulnerability Description

The vulnerabilities arise from incorrect processing of BGP update messages with crafted EVPN attributes.

Affected Systems and Versions

Affected Product: Cisco IOS XR Software
Vendor: Cisco
Affected Version: Not applicable (n/a)

Exploitation Mechanism

Attackers can exploit the vulnerabilities by sending BGP EVPN update messages with modified attributes to affected systems.

Mitigation and Prevention

Learn how to mitigate and prevent the CVE-2019-16023 vulnerability.

Immediate Steps to Take

Implement filters to block harmful BGP update messages.
Regularly monitor BGP traffic for anomalies.

Long-Term Security Practices

Conduct regular security assessments and audits.
Keep systems updated with the latest security patches.

Patching and Updates

Apply relevant patches and updates provided by Cisco to address the vulnerabilities.