CVE-2024-39547: Junos OS and Junos OS Evolved: cRPD: Receipt of crafted TCP traffic can trigger high CPU utilization

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.