CVE-2024-39547

/// Technical description

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: 233

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References