A Missing Release of Memory after Effective Lifetime vulnerability in the Periodic Packet Management Daemon (ppmd) of Juniper Networks Junos OS and Junos OS Evolved allows an unauthenticated adjacent attacker to cause a Denial-of-Service (DoS).

When a BFD session configured with authentication flaps, ppmd memory can leak. Whether the leak happens depends on a race condition which is outside the attackers control. This issue only affects BFD operating in distributed aka delegated (which is the default behavior) or inline mode.
 

Whether the leak occurs can be monitored with the following CLI command:

> show ppm request-queue

where a continuously increasing number of pending requests is indicative of the leak. 

This issue affects:

Junos OS:

• All versions before 21.2R3-S8,
• 21.4 versions before 21.4R3-S7,
• 22.1 versions before 22.1R3-S4,
• 22.2 versions before 22.2R3-S4, 
• 22.3 versions before 22.3R3,
• 22.4 versions before 22.4R2-S2, 22.4R3.

• All versions before 21.2R3-S8-EVO,
• 21.4-EVO versions before 21.4R3-S7-EVO,
• 22.2-EVO versions before 22.2R3-S4-EVO,
• 22.3-EVO versions before 22.3R3-EVO,
• 22.4-EVO versions before 22.4R3-EVO.

To be exposed to this issue, BFD with authentication like in the following examples needs to be configured:

[ protocols <protocol> ... bfd-liveness-detection authentication ]
[ routing-options ... bfd-liveness-detection authentication ]

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

This issue was seen during production usage.

The following software releases have been updated to resolve this specific issue:
Junos OS: 21.2R3-S8, 21.4R3-S7, 22.1R3-S4, 22.2R3-S4, 22.3R3, 22.4R2-S2, 22.4R3, 23.2R1, and all subsequent releases;
Junos OS Evolved: 21.2R3-S8-EVO, 21.4R3-S7-EVO, 22.2R3-S4-EVO, 22.3R3-EVO, 22.4R3-EVO, 23.2R1-EVO, and all subsequent releases.
 

This issue is being tracked as 1480648 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).

There are no known workarounds for this issue, but:

1. delegate processing can be disabled to prevent this issue from happening:

2. ppmd can be restarted to recover the leaked memory.

2024-07-10: Initial Publication
2024-07-12: Removed misleading 23.1 and 23.2 versions from affected releases section
2024-09-13: Minor formatting change to CVSS field

• 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