CVE-2024-21591 Explained : Impact and Mitigation

This article provides detailed information about CVE-2024-21591, a security vulnerability found in Junos OS affecting SRX Series and EX Series devices.

Understanding CVE-2024-21591

This CVE entry highlights a critical security vulnerability in Junos OS that could potentially lead to Denial of Service (DoS) or Remote Code Execution (RCE) attacks on Juniper Networks' SRX Series and EX Series devices.

What is CVE-2024-21591?

An Out-of-bounds Write vulnerability in J-Web of Juniper Networks Junos OS allows an unauthenticated attacker to exploit an insecure function, leading to potential memory overwrites. This vulnerability poses a significant risk of a malicious actor causing a DoS, RCE, and gaining root privileges on the targeted device.

The Impact of CVE-2024-21591

The impact of this vulnerability is categorized as critical, with a CVSS v3.1 base score of 9.8 - indicating a high-severity issue. The attack complexity is low, with a network vector that can result in high availability, confidentiality, and integrity impacts.

Technical Details of CVE-2024-21591

This section delves into the specific technical aspects of the CVE, including the vulnerability description, affected systems and versions, and the exploitation mechanism.

Vulnerability Description

The vulnerability arises from an insecure function in J-Web of Junos OS, allowing unauthorized users to trigger an Out-of-bounds Write situation and potentially execute malicious code.

Affected Systems and Versions

Juniper Networks' Junos OS versions earlier than 20.4R3-S9, 21.2R3-S7, 21.3R3-S5, 21.4R3-S5, 22.1R3-S4, 22.2R3-S3, 22.3R3-S2, and 22.4R2-S2, 22.4R3 on SRX Series and EX Series devices.

Exploitation Mechanism

An unauthenticated, network-based attacker can exploit this vulnerability to achieve DoS, RCE, and potentially gain root access by overwriting memory through the insecure function in J-Web.

Mitigation and Prevention

To address CVE-2024-21591 effectively, it's crucial to implement immediate steps for mitigation and adopt long-term security practices to prevent similar vulnerabilities in the future.

Immediate Steps to Take

Disable J-Web service on affected devices or restrict access to only trusted hosts to mitigate the risk of exploitation.

Long-Term Security Practices

Regularly update and patch Junos OS with the recommended software releases provided by Juniper Networks, following a robust security update strategy to stay protected against known vulnerabilities.

Patching and Updates

Juniper Networks has released updated software versions to address CVE-2024-21591. Ensure to upgrade to Junos OS versions such as 20.4R3-S9, 21.2R3-S7, 21.3R3-S5, 21.4R3-S5, 22.1R3-S4, 22.2R3-S3, 22.3R3-S2, 22.4R2-S2, 22.4R3, 23.2R1-S1, 23.2R2, 23.4R1, or subsequent releases as recommended by Juniper Networks.

This information is crucial to safeguard your Juniper Networks SRX Series and EX Series devices against potential security threats arising from CVE-2024-21591.