CVE-2024-21611: In a jflow scenario continuous route churn will cause a memory leak and eventually an rpd crash

What it is

A Missing Release of Memory after Effective Lifetime vulnerability in the Routing Protocol Daemon (rpd) of Juniper Networks Junos OS and Junos OS Evolved allows an unauthenticated, network-based attacker to cause a Denial of Service (DoS).

In a Juniper Flow Monitoring (jflow) scenario route churn that causes BGP next hops to be updated will cause a slow memory leak and eventually a crash and restart of rpd.

Thread level memory utilization for the areas where the leak occurs can be checked using the below command:

user@host> show task memory detail | match so_in so_in6 28 32 344450 11022400 344760 11032320 so_in 8 16 1841629 29466064 1841734 29467744 This issue affects:

Junos OS

• 21.4 versions earlier than 21.4R3;
• 22.1 versions earlier than 22.1R3;
• 22.2 versions earlier than 22.2R3.

Junos OS Evolved

• 21.4-EVO versions earlier than 21.4R3-EVO;
• 22.1-EVO versions earlier than 22.1R3-EVO;
• 22.2-EVO versions earlier than 22.2R3-EVO.

This issue does not affect:

Juniper Networks Junos OS versions earlier than 21.4R1.

Juniper Networks Junos OS Evolved versions earlier than 21.4R1.

Am I affected?

This issue only happens when jflow is configured:

[ services flow-monitoring (version-ipfix|version9) ]

Workarounds

Although not a workaround, it is advised to monitor the memory utilization proactively and when it reaches 85% of total RE memory, restart rpd or reboot the system.

Exploitation

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