An Improper Handling of Exceptional Conditions vulnerability in the Routing Protocol Daemon (RPD) of Juniper Networks Junos OS and Junos OS Evolved allows an attacker sending a specific malformed BGP update message to cause the session to reset, resulting in a Denial of Service (DoS). Continued receipt and processing of these malformed BGP update messages will create a sustained Denial of Service (DoS) condition.

Upon receipt of a BGP update message over an established BGP session containing a specifically malformed tunnel encapsulation attribute, when segment routing is enabled, internal processing of the malformed attributes within the update results in improper parsing of remaining attributes, leading to session reset:

BGP SEND Notification code 3 (Update Message Error) subcode 1 (invalid attribute list)

Only systems with segment routing enabled are vulnerable to this issue.

This issue affects eBGP and iBGP, in both IPv4 and IPv6 implementations, and requires a remote attacker to have at least one established BGP session.
 

This issue affects:

Junos OS:

• All versions before 21.4R3-S8,
• from 22.2 before 22.2R3-S4,
• from 22.3 before 22.3R3-S3,
• from 22.4 before 22.4R3-S3,
• from 23.2 before 23.2R2-S1,
• from 23.4 before 23.4R1-S2, 23.4R2.

Junos OS Evolved: 

• All versions before 21.4R3-S8-EVO,
• from 22.2-EVO before 22.2R3-S4-EVO,
• from 22.3-EVO before 22.3R3-S3-EVO,
• from 22.4-EVO before 22.4R3-S3-EVO,
• from 23.2-EVO before 23.2R2-S1-EVO,
• from 23.4-EVO before 23.4R1-S2-EVO, 23.4R2-EVO.

[ protocols bgp group <name> family inet segment-routing-te ] (IPv4)

or

[ protocols bgp group <name> family inet6 segment-routing-te ] (IPv6)

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

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

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

Junos OS: 21.4R3-S8, 22.2R3-S4, 22.3R3-S3, 22.4R3-S3, 23.2R2-S1, 23.4R1-S2, 23.4R2, 24.2R1, and all subsequent releases.
Junos OS Evolved: 21.4R3-S8-EVO, 22.2R3-S4-EVO, 22.3R3-S3-EVO, 22.4R3-S3-EVO, 23.2R2-S1-EVO, 23.4R1-S2-EVO, 23.4R2-EVO, 24.2R1-EVO, and all subsequent releases.
 

This issue is being tracked as 1787290 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).

Enabling BGP Error Tolerance will mitigate this issue:

2024-07-10: Initial Publication
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
• https://www.cve.org/CVERecord?id=CVE-2024-39555