CVE-2021-0228 : Security Advisory and Response

An improper check for unusual or exceptional conditions vulnerability in Juniper Networks MX Series platforms with Trio-based MPC (Modular Port Concentrator) deployed in EVPN-VXLAN configuration could allow an attacker to trigger DDoS protection unexpectedly, leading to a Denial of Service (DoS) condition.

Understanding CVE-2021-0228

This CVE impacts Junos OS on MX Series platforms by causing a DDoS LACP violation upon receiving specific layer 2 frames in EVPN-VXLAN deployment.

What is CVE-2021-0228?

CVE-2021-0228 is a vulnerability in Juniper Networks MX Series platforms that could be exploited by an attacker to cause a Denial of Service (DoS) condition by triggering DDoS protection unexpectedly.

The Impact of CVE-2021-0228

The vulnerability may allow an attacker to sustain the DoS condition by sending specific Layer 2 traffic, impacting the network's availability.

Technical Details of CVE-2021-0228

The vulnerability affects Juniper Networks Junos OS on MX Series platforms with specific versions prior to the patched releases.

Vulnerability Description

The issue arises from an improper check for unusual conditions in the EVPN-VXLAN configuration, potentially leading to DDoS LACP violations.

Affected Systems and Versions

Junos OS versions affected include 15.1, 17.3, 17.4, 18.1, 18.2, 18.3, 18.4, 19.1, 19.2, 19.3, 19.4, 20.1, 20.2, and 20.3 on MX Series platforms.

Exploitation Mechanism

Juniper SIRT has not detected any instances of malicious exploitation of this vulnerability.

Mitigation and Prevention

It is essential to apply the provided software updates to mitigate the risk associated with CVE-2021-0228.

Immediate Steps to Take

Disable DDoS for LACP by applying the specified configurations to prevent exploitation.

Long-Term Security Practices

Regularly check for security advisories and update Junos OS to prevent potential security vulnerabilities.

Patching and Updates

Juniper Networks has released patches for Junos OS versions affected by CVE-2021-0228.