CVE-2021-31370 : What You Need to Know

An Incomplete List of Disallowed Inputs vulnerability in Packet Forwarding Engine (PFE) of Juniper Networks Junos OS on QFX5000 Series and EX4600 Series allows an adjacent unauthenticated attacker which sends a high rate of specific multicast traffic to cause control traffic received from the network to be dropped. This will impact control protocols (including but not limited to routing-protocols) and lead to a Denial of Service (DoS). Continued receipt of this specific multicast traffic will create a sustained Denial of Service (DoS) condition. This issue affects Juniper Networks Junos OS on QFX5000 and EX4600 Series.

Understanding CVE-2021-31370

This CVE involves an Incomplete List of Disallowed Inputs vulnerability that can result in a Denial of Service (DoS) on the affected devices.

What is CVE-2021-31370?

CVE-2021-31370 is a vulnerability in Juniper Networks Junos OS on QFX5000 Series and EX4600 Series that allows an attacker to disrupt control traffic by sending specific multicast traffic, leading to a Denial of Service situation.

The Impact of CVE-2021-31370

The vulnerability can impact control protocols on the affected devices and result in a Denial of Service (DoS) condition when specific multicast traffic is continuously received.

Technical Details of CVE-2021-31370

This section covers the technical details of the CVE including the vulnerability description, affected systems, and exploitation mechanism.

Vulnerability Description

The vulnerability lies in the Packet Forwarding Engine (PFE) of Juniper Networks Junos OS on QFX5000 Series and EX4600 Series, allowing an adjacent unauthenticated attacker to disrupt control traffic with specific multicast traffic.

Affected Systems and Versions

The impacted systems include QFX5000 Series and EX4600 Series running Juniper Networks Junos OS versions prior to 21.1R2.

Exploitation Mechanism

Juniper SIRT has not detected any exploitation of this vulnerability, but the potential attack vector is through sending a high rate of specific multicast traffic.

Mitigation and Prevention

Learn how to address and prevent the CVE-2021-31370 vulnerability to secure your network.

Immediate Steps to Take

Apply the provided software updates that resolve the specific issue and consider additional security measures.

Long-Term Security Practices

Implement loopback filters to drop unnecessary multicast traffic, and refer to relevant documentation for further hardening practices.

Patching and Updates

Ensure that your Juniper Networks Junos OS is updated to the patched versions to mitigate the vulnerability.