CVE-2021-31357 : Vulnerability Insights and Analysis

A command injection vulnerability in tcpdump command processing on Juniper Networks Junos OS Evolved allows an attacker to execute arbitrary shell commands, bypassing command restrictions. The vulnerability affects several versions of Junos OS Evolved, allowing unauthorized access to the shell.

Understanding CVE-2021-31357

This CVE describes a command injection vulnerability in tcpdump processing on Juniper Networks Junos OS Evolved, enabling an attacker to execute unauthorized shell commands within the user context.

What is CVE-2021-31357?

The CVE-2021-31357 vulnerability in Junos OS Evolved allows an authenticated attacker to bypass configured access protections and execute arbitrary shell commands within the current user context.

The Impact of CVE-2021-31357

The vulnerability enables an attacker to bypass command restrictions and execute commands beyond their assigned privilege level, potentially compromising system integrity and confidentiality.

Technical Details of CVE-2021-31357

This section outlines the specific details of the vulnerability, including the description, affected systems, and exploitation mechanism.

Vulnerability Description

The vulnerability allows an attacker with authenticated CLI access to execute arbitrary shell commands, bypassing command authorization restrictions.

Affected Systems and Versions

Juniper Networks Junos OS Evolved versions prior to 20.3R2-S1-EVO, 20.4R2-S2-EVO, 21.1R2-EVO, 21.2R1-S1-EVO, and 21.2R2-EVO are affected by this vulnerability.

Exploitation Mechanism

An attacker can exploit this vulnerability to execute unauthorized shell commands within the context of the current user, bypassing configured access protections.

Mitigation and Prevention

In this section, we discuss the steps to mitigate the impact of CVE-2021-31357 and prevent future occurrences.

Immediate Steps to Take

Update to the latest software releases provided by Juniper Networks to resolve this specific issue.

Long-Term Security Practices

Implement access lists or firewall filters to limit CLI access only from trusted hosts and administrators.
Restrict access to specific CLI commands to authorized administrators.

Patching and Updates

Juniper Networks has released software updates for Junos OS Evolved 20.3R2-S1-EVO, 20.4R2-S2-EVO, 21.1R2-EVO, 21.2R1-S1-EVO, 21.2R2-EVO, 21.3R1-EVO, and subsequent releases to address this vulnerability.