CVE-2021-0252 : Vulnerability Insights and Analysis

A local code execution vulnerability in Juniper Networks Junos OS affecting NFX Series devices has been identified, allowing attackers to escalate privileges via JDMD.

Understanding CVE-2021-0252

This CVE involves a critical vulnerability in Juniper Networks Junos OS that could lead to privilege escalation through a local code execution issue.

What is CVE-2021-0252?

NFX Series devices running Junos OS are exposed to a flaw that permits malicious actors to execute arbitrary code and elevate privileges via the Junos Device Management Daemon (JDMD) process.

The Impact of CVE-2021-0252

The vulnerability poses a high risk, with the potential for local attackers to gain elevated privileges on affected devices, compromising confidentiality, integrity, and system availability.

Technical Details of CVE-2021-0252

The vulnerability is classified under CWE-77 (Command Injection), with a CVSS v3.1 base score of 7.8, indicating a high severity threat with low privileges required for exploitation through a local attack vector.

Vulnerability Description

The flaw affects Junos OS versions on NFX Series prior to specific patched releases, enabling attackers to exploit the JDMD process to execute malicious commands.

Affected Systems and Versions

Juniper Networks Junos OS versions 18.1R1 and later up to certain releases like 18.4R3-S4 are impacted, excluding versions predating 18.1R1. NFX Series devices are vulnerable.

Exploitation Mechanism

Attack complexity is low, and no user interaction is needed. Malicious local users could leverage the vulnerability to gain unauthorized access and perform privilege escalation activities.

Mitigation and Prevention

Given the severity of CVE-2021-0252, immediate action and long-term security practices are crucial to safeguard affected systems.

Immediate Steps to Take

Juniper Networks recommends applying the designated software releases, including Junos OS versions 18.2R3-S5 and subsequent updates, to address the vulnerability and prevent exploitation.

Long-Term Security Practices

Implement access controls like firewalls to restrict unauthorized access and enhance network monitoring to detect any suspicious activity targeting the vulnerable JDMD process.

Patching and Updates

Scheduled patching of all affected Junos OS installations to the recommended versions is essential for mitigating the risk posed by CVE-2021-0252.