CVE-2019-10876 Explained : Impact and Mitigation

A vulnerability has been found in OpenStack Neutron versions 11.x prior to 11.0.7, 12.x prior to 12.0.6, and 13.x prior to 13.0.3 that can be exploited by an authenticated user. This vulnerability affects Neutron deployments using the neutron-openvswitch-agent.

Understanding CVE-2019-10876

This CVE involves a security issue in OpenStack Neutron that impacts the configuration of networks on compute nodes.

What is CVE-2019-10876?

CVE-2019-10876 is a vulnerability in OpenStack Neutron versions 11.x, 12.x, and 13.x that allows an authenticated user to disrupt network configuration on compute nodes by creating specific security groups.

The Impact of CVE-2019-10876

The vulnerability results in Neutron being unable to configure networks on compute nodes where the specified security groups exist due to a KeyError in the Open vSwitch (OVS) firewall. This affects all Neutron deployments utilizing the neutron-openvswitch-agent.

Technical Details of CVE-2019-10876

This section provides more technical insights into the vulnerability.

Vulnerability Description

The issue arises when an authenticated user creates two security groups with separate or overlapping port ranges, causing a disruption in network configuration on compute nodes.

Affected Systems and Versions

OpenStack Neutron versions 11.x before 11.0.7
OpenStack Neutron versions 12.x before 12.0.6
OpenStack Neutron versions 13.x before 13.0.3

Exploitation Mechanism

An authenticated user can exploit this vulnerability by creating specific security groups with certain port range configurations, leading to network configuration issues on compute nodes.

Mitigation and Prevention

To address CVE-2019-10876, follow these mitigation strategies:

Immediate Steps to Take

Update Neutron to versions 11.0.7, 12.0.6, or 13.0.3, where the vulnerability is patched.
Implement strict security group rules to prevent unauthorized configurations.

Long-Term Security Practices

Regularly monitor and audit security group configurations.
Train users on secure security group practices to prevent misconfigurations.

Patching and Updates

Apply the necessary patches provided by OpenStack to fix the vulnerability.