A Time-of-check Time-of-use (TOCTOU) Race Condition vulnerability in the Routing Protocol Daemon (rpd) of Juniper Networks Junos OS and Junos OS Evolved allows an unauthenticated attacker with an established BGP session to cause a Denial of Service (DoS).

In a BGP multipath scenario, when one of the contributing routes is flapping often and rapidly, rpd may crash. As this crash depends on whether a route is a contributing route, and on the internal timing of the events triggered by the flap this vulnerability is outside the direct control of a potential attacker.

This issue affects:

Juniper Networks Junos OS

• 19.2 versions prior to 19.2R3-S6;
• 20.2 versions prior to 20.2R3-S4;
• 20.3 versions prior to 20.3R3-S3;
• 20.4 versions prior to 20.4R3-S4;
• 21.1 versions prior to 21.1R3;
• 21.2 versions prior to 21.2R2;
• 21.3 versions prior to 21.3R2.

Juniper Networks Junos OS Evolved

• All versions prior to 20.4R3-S4-EVO;
• 21.1-EVO version 21.1R1-EVO  and later versions;
• 21.2-EVO versions prior to 21.2R2-EVO;
• 21.3-EVO versions prior to 21.3R2-EVO.

This issue does not affect:
Juniper Networks Junos OS versions 19.2 versions prior to 19.2R2, 19.3R1 and above prior to 20.2R1.

Juniper Networks Junos OS Evolved versions prior to 20.2R1-EVO.

A device can only be affected if the following BGP multipath configuration is in place:

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

This issue was found during internal product security testing or research.

This issue has been assigned CVE-2022-22225.

The following software releases have been updated to resolve this specific issue:

Junos OS: 19.2R3-S6, 20.2R3-S4, 20.3R3-S3, 20.4R3-S4, 21.1R2, 21.2R2, 21.3R2, 21.4R1, and all subsequent releases.

Junos OS Evolved: 20.4R3-S4-EVO, 21.2R2-EVO, 21.3R2-EVO, 21.4R1-EVO, and all subsequent releases.

This issue is being tracked as PR 1611128 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).

IMPLEMENTATION:

Software Releases, patches and updates are available at https://support.juniper.net/support/downloads/.

• 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-2022-22225 at cve.mitre.org