An Unsupported Feature in the UI vulnerability in Juniper Networks Junos OS on MX Series and EX9200 Series allows an unauthenticated, network-based attacker to cause partial impact to the integrity of the device.

If the "tcp-reset" option is added to the "reject" action in an IPv6 filter which matches on "payload-protocol", packets are permitted instead of rejected. This happens because the payload-protocol match criteria is not supported in the kernel filter causing it to accept all packets without taking any other action. As a fix the payload-protocol match will be treated the same as a "next-header" match to avoid this filter bypass.

This issue doesn't affect IPv4 firewall filters.
 

This issue affects Juniper Networks Junos OS on MX Series and EX9200 Series:

• All versions earlier than 20.4R3-S7;
• 21.1 versions earlier than 21.1R3-S5;
• 21.2 versions earlier than 21.2R3-S5;
• 21.3 versions earlier than 21.3R3-S4;
• 21.4 versions earlier than 21.4R3-S4;
• 22.1 versions earlier than 22.1R3-S2;
• 22.2 versions earlier than 22.2R3-S2;
• 22.3 versions earlier than 22.3R2-S2, 22.3R3;
• 22.4 versions earlier than 22.4R1-S2, 22.4R2-S2, 22.4R3.

To be exposed to this issue a configuration utilizing an IPv6 firewall filter with the tcp-reset option like the following needs to be present:

Juniper SIRT is not aware of any malicious exploitation of this vulnerability.

This issue was seen during production usage.

This issue has been assigned CVE-2024-21607.

The following software releases have been updated to resolve this specific issue: 20.4R3-S7, 21.1R3-S5, 21.2R3-S5, 21.3R3-S4, 21.4R3-S4, 22.1R3-S2, 22.2R3-S2, 22.3R2-S2, 22.3R3, 22.4R1-S2, 22.4R2-S2, 22.4R3*, 23.2R1, and all subsequent releases. (* pending publication)

This issue is being tracked as PR 1689224 which is visible on the Customer Support website.

Note: Juniper SIRT's policy is not to evaluate releases which are beyond End of Engineering (EOE) or End of Life (EOL).

A workarounds is to replace the payload-protocol match with a next-header match like in the following example:

2024-01-10: Initial Publication

• KB16613: Overview of the Juniper Networks SIRT Quarterly Security Bulletin Publication Process [juniper.net]
• KB16765: In which releases are vulnerabilities fixed? [juniper.net]
• KB16446: Common Vulnerability Scoring System (CVSS) and Juniper's Security Advisories [juniper.net]
• Report a Security Vulnerability - How to Contact the Juniper Networks Security Incident Response Team
• CVE-2024-21607 at cve.mitre.org