CVE-2021-0247 : Vulnerability Insights and Analysis

A detailed article on the CVE-2021-0247 vulnerability in Juniper Networks Junos OS affecting QFX Series and PTX Series devices.

Understanding CVE-2021-0247

This CVE describes a Race Condition vulnerability in the firewall process of Junos OS, allowing attackers to bypass firewall rule sets on input loopback filters.

What is CVE-2021-0247?

A Race Condition vulnerability in Juniper Networks Junos OS permits an attacker to evade firewall rule sets on input loopback filters of QFX Series and PTX Series devices.

The Impact of CVE-2021-0247

The vulnerability affects various versions of Junos OS prior to specific releases, potentially leading to firewall rule bypass on loopback filter inputs.

Technical Details of CVE-2021-0247

This section outlines the vulnerability's description, affected systems, and the exploitation mechanism.

Vulnerability Description

The flaw allows malicious actors to circumvent firewall rule sets applied to input loopback filters on Junos OS devices.

Affected Systems and Versions

Multiple versions of Junos OS on QFX Series and PTX Series devices are impacted by this vulnerability.

Exploitation Mechanism

The vulnerability relies on a Race Condition to manipulate firewall rules, potentially compromising network security.

Mitigation and Prevention

Discover the immediate steps, long-term practices, and patching suggestions to mitigate the CVE-2021-0247 risk.

Immediate Steps to Take

Stay informed with the Juniper Networks advisory and apply recommended software updates to affected versions.

Long-Term Security Practices

Regularly monitor firewall rule sets, PFE firewall counters, and keep abreast of security advisories from Juniper Networks.

Patching and Updates

Ensure the installation of the specified software versions to resolve this vulnerability and enhance your devices' security.