CVE-2023-28961 Explained : Impact and Mitigation

An Improper Handling of Unexpected Data Type vulnerability in IPv6 firewall filter processing of Juniper Networks Junos OS on the ACX Series devices prevents a firewall filter with the term 'from next-header ah' from being properly installed in the packet forwarding engine (PFE), potentially allowing attackers to send valid packets through the device.

Understanding CVE-2023-28961

This CVE-2023-28961 vulnerability impacts Juniper Networks Junos OS on ACX Series devices, affecting various versions prior to specific releases.

What is CVE-2023-28961?

The vulnerability arises from improper handling of unexpected data types in the IPv6 firewall filter processing of Juniper Networks Junos OS, specifically related to the term 'from next-header ah'. Attackers could exploit this issue to send valid packets through the device that were intended to be dropped.

The Impact of CVE-2023-28961

The impact of this vulnerability is rated as medium severity, with a CVSS v3.1 base score of 5.8. While the attack complexity is low, it could lead to a compromise of data integrity under certain circumstances.

Technical Details of CVE-2023-28961

This section provides insights into the specific technical aspects of the vulnerability:

Vulnerability Description

The vulnerability results in the failure to properly install a firewall filter with the term 'from next-header ah', potentially allowing attackers to bypass intended packet filtering rules.

Affected Systems and Versions

Juniper Networks Junos OS on ACX Series devices is impacted by this vulnerability in versions prior to 20.2R3-S7, 20.4R3-S4, 21.1R3-S3, 21.2R3-S4, 21.3R3, 21.4R3, and 22.1R2.

Exploitation Mechanism

At present, there are no known instances of malicious exploitation of this particular vulnerability by Juniper SIRT.

Mitigation and Prevention

To address CVE-2023-28961 and enhance system security, consider the following mitigation strategies:

Immediate Steps to Take

Verify and apply the necessary software updates to Juniper Networks Junos OS to versions 20.2R3-S7, 20.4R3-S4, 21.1R3-S3, 21.2R3-S4, 21.3R3, 21.4R3, 22.1R2, 22.2R1, or subsequent releases.
Monitor for any unusual or unexpected network activity that may indicate exploitation of the vulnerability.

Long-Term Security Practices

Regularly update and patch Juniper Networks Junos OS to the latest available versions.
Implement network segmentation and access controls to minimize the potential impact of vulnerabilities.

Patching and Updates

Juniper Networks has released software updates to address this specific vulnerability. Ensure prompt application of these updates to mitigate the risk of exploitation.