CVE-2021-0234 : Exploit Details and Defense Strategies

This article provides an overview of CVE-2021-0234, a vulnerability in Junos OS affecting QFX5100-96S devices leading to DDoS protection malfunction.

Understanding CVE-2021-0234

CVE-2021-0234 is a vulnerability in Juniper Networks Junos OS QFX5100-96S devices, causing issues with DDoS protection functionality.

What is CVE-2021-0234?

The vulnerability results in improper initialization, preventing ddos-protection configuration changes beyond default settings, impacting only QFX5100-96S devices.

The Impact of CVE-2021-0234

This vulnerability affects Juniper Networks Junos OS versions 17.3 to 19.4 on QFX5100-96S, impacting DDoS protection efficacy under CLI configuration.

Technical Details of CVE-2021-0234

This section covers the vulnerability description, affected systems, and exploitation mechanism.

Vulnerability Description

DDoS protection settings fail to apply correctly on Junos OS QFX5100-96S, allowing CPU-bound packets to overwhelm packet forwarding engine without mitigation.

Affected Systems and Versions

Juniper Networks Junos OS versions 17.3 to 19.4 on QFX5100-96S devices are vulnerable to this DDoS protection issue.

Exploitation Mechanism

No known malicious exploits exist for this vulnerability as reported by Juniper SIRT.

Mitigation and Prevention

Learn about immediate steps, long-term security practices, and available patches.

Immediate Steps to Take

Administrators can manually enable ddos-protection on affected devices using the provided command.

Long-Term Security Practices

Regularly update Junos OS software to the recommended versions to safeguard against vulnerabilities like CVE-2021-0234.

Patching and Updates

Install the latest software releases, including versions 17.3R3-S10, 17.4R3-S4, 18.1R3-S10, 18.2R3-S3, 18.3R3-S2, 18.4R2-S4, 18.4R3-S1, 19.1R3, 19.1R3-S4, 19.2R2, 19.3R3, 19.4R2, 20.1R1, or later, to address CVE-2021-0234.