CVE-2024-21596 Explained : Impact and Mitigation

This CVE record pertains to a Heap-based Buffer Overflow vulnerability in the Routing Protocol Daemon (RPD) of Juniper Networks Junos OS and Junos OS Evolved. The vulnerability allows an unauthenticated, network-based attacker to trigger a Denial of Service (DoS) by exploiting specific BGP UPDATE messages.

Understanding CVE-2024-21596

This vulnerability affects Juniper Networks Junos OS and Junos OS Evolved, impacting devices with NSR enabled. The issue arises from a memory overwrite caused by the reception of certain BGP UPDATE messages, leading to an RPD crash and restart in the backup Routing Engine, potentially resulting in a sustained DoS condition.

What is CVE-2024-21596?

The Heap-based Buffer Overflow vulnerability in RPD of Juniper Networks Junos OS and Junos OS Evolved enables attackers to disrupt network services through a DoS attack. The primary Routing Engine is unaffected, and there is no impact on traffic. However, the issue requires an established BGP session with affected systems.

The Impact of CVE-2024-21596

The vulnerability affects devices running Juniper Networks Junos OS and Junos OS Evolved with specific versions listed as vulnerable. Unauthorized exploitation of this issue could lead to service disruption and potentially impact network availability.

Technical Details of CVE-2024-21596

This vulnerability results from a specific BGP UPDATE message triggering a memory overwrite in the RPD of Juniper Networks Junos OS and Junos OS Evolved. Here are more technical details:

Vulnerability Description

The vulnerability allows unauthenticated attackers to cause a DoS by sending malicious BGP UPDATE messages, disrupting the backup Routing Engine.

Affected Systems and Versions

Juniper Networks Junos OS versions earlier than 20.4R3-S9 and Junos OS Evolved versions prior to 21.3 exhibit vulnerability to this issue. The specific affected versions are listed in the descriptions provided.

Exploitation Mechanism

Attackers exploit the vulnerability by sending crafted BGP UPDATE messages to devices with NSR enabled, prompting a memory overwrite and subsequent RPD crash.

Mitigation and Prevention

To address CVE-2024-21596, follow these mitigation and prevention measures:

Immediate Steps to Take

Monitor for any unusual BGP UPDATE messages.
Implement vendor-provided patches and updates promptly.

Long-Term Security Practices

Regularly update and patch network devices.
Monitor network traffic for anomalies that may indicate exploitation attempts.

Patching and Updates

Juniper Networks has released updated software versions to resolve this specific vulnerability for Junos OS and Junos OS Evolved. Applying these patches is essential to mitigate the risk associated with this CVE.

Remember, maintaining up-to-date software and adhering to sound security practices are crucial in safeguarding network infrastructures against potential threats.

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For more details, refer to the official advisory from Juniper Networks: JSA75735.