An Improper Handling of Exceptional Conditions vulnerability in the rpd-server of Juniper Networks Junos OS and Junos OS Evolved within cRPD allows an unauthenticated network-based attacker sending crafted TCP traffic to the routing engine (RE) to cause a CPU-based Denial of Service (DoS).

If specially crafted TCP traffic is received by the control plane, or a TCP session terminates unexpectedly, it will cause increased control plane CPU utilization by the rpd-server process.

While not explicitly required, the impact is more severe when RIB sharding is enabled.

Task accounting shows unexpected reads by the RPD Server jobs for shards:

user@junos> show task accounting detail
...
read:RPD Server.0.0.0.0+780.192.168.0.78+48886 TOT:00000003.00379787 MAX:00000000.00080516 RUNS: 233888\
read:RPD Server.0.0.0.0+780.192.168.0.78+49144 TOT:00000004.00007565 MAX:00000000.00080360 RUNS: 233888\
read:RPD Server.0.0.0.0+780.192.168.0.78+49694 TOT:00000003.00600584 MAX:00000000.00080463 RUNS: 233888\
read:RPD Server.0.0.0.0+780.192.168.0.78+50246 TOT:00000004.00346998 MAX:00000000.00080338 RUNS: 233888\

This issue affects:

Junos OS with cRPD: 

• All versions before 21.2R3-S8, 
• 21.4 before 21.4R3-S7, 
• 22.1 before 22.1R3-S6, 
• 22.2 before 22.2R3-S4, 
• 22.3 before 22.3R3-S3, 
• 22.4 before 22.4R3-S2, 
• 23.2 before 23.2R2-S2, 
• 24.2 before 24.2R2; 

Junos OS Evolved with cRPD: 

• All versions before 21.4R3-S7-EVO, 
• 22.2 before 22.2R3-S4-EVO, 
• 22.3 before 22.3R3-S3-EVO, 
• 22.4 before 22.4R3-S2-EVO, 
• 23.2 before 23.2R2-EVO.

rpd-server is enabled by default in cRPD. No specific configuration is required to be vulnerable to this issue.

BGP RIB sharding is enabled using the following configuration:

[set system processes routing bgp rib-sharding]

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-S6, 22.2R3-S4, 22.3R3-S3, 22.4R3-S2, 23.2R2-S2, 23.4R1, and all subsequent releases.
Junos OS Evolved 21.4R3-S7-EVO, 22.2R3-S4-EVO, 22.3R3-S3-EVO, 22.4R3-S2-EVO, 23.2R2-EVO, 23.4R1-EVO, and all subsequent releases.

This issue is being tracked as 1765417 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.

2024-10-09: 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