CVE-2021-0206 Explained : Impact and Mitigation

A NULL Pointer Dereference vulnerability in Juniper Networks Junos OS allows an attacker to send a specific packet causing the packet forwarding engine (PFE) to crash and restart, resulting in a Denial of Service (DoS) attack. This vulnerability, affecting Juniper Networks NFX Series and SRX Series platforms, poses a high availability impact with a CVSS base score of 7.5.

Understanding CVE-2021-0206

This CVE highlights a vulnerability in Juniper Networks Junos OS that can be exploited to crash the PFE and initiate a sustained DoS attack.

What is CVE-2021-0206?

The CVE addresses a NULL Pointer Dereference issue in Juniper Networks Junos OS, impacting NFX Series and SRX Series platforms when SSL Proxy is configured. Attackers can repeatedly disable the PFE by sending specific packets, leading to a sustained DoS.

The Impact of CVE-2021-0206

The vulnerability causes the PFE to crash and restart, resulting in a DoS. It affects the availability of services on impacted Junos OS versions for NFX Series and SRX Series platforms.

Technical Details of CVE-2021-0206

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

Vulnerability Description

The vulnerability allows an attacker to crash the PFE in Juniper Networks Junos OS, causing a sustained DoS by continuously sending specific packets.

Affected Systems and Versions

Junos OS versions for NFX Series and SRX Series platforms are affected, including 18.3*, 18.4, 19.1, 19.2, and 19.3 prior to specific release versions.

Exploitation Mechanism

Exploiting this vulnerability involves sending crafted packets to crash the PFE, impacting the availability of services on affected devices.

Mitigation and Prevention

Discover immediate steps to take, long-term security practices, and the importance of patching and updates.

Immediate Steps to Take

Users are advised to install the updated software releases provided by Juniper Networks to mitigate the vulnerability and prevent DoS attacks.

Long-Term Security Practices

Strengthening network security measures, monitoring traffic for malicious patterns, and staying informed about potential vulnerabilities can enhance long-term security.

Patching and Updates

Regularly applying software patches and updates is crucial in safeguarding network infrastructure against known vulnerabilities.