CVE-2024-21600: Junos OS: PTX Series: In an FTI scenario MPLS packets hitting reject next-hop will cause a host path wedge condition
An Improper Neutralization of Equivalent Special Elements vulnerability in the Packet Forwarding Engine (PFE) of Juniper Networks Junos OS on PTX Series allows a unauthenticated, adjacent attacker to cause a Denial of Service (DoS).
When MPLS packets are meant to be sent to a flexible tunnel interface (FTI) and if the FTI tunnel is down, these will hit the reject NH, due to which the packets get sent to the CPU and cause a host path wedge condition. This will cause the FPC to hang and requires a manual restart to recover.
Please note that this issue specifically affects PTX1000, PTX3000, PTX5000 with FPC3, PTX10002-60C, and PTX10008/16 with LC110x. Other PTX Series devices and Line Cards (LC) are not affected.
The following log message can be seen when the issue occurs:
Cmerror Op Set: Host Loopback: HOST LOOPBACK WEDGE DETECTED IN PATH ID <id> (URI: /fpc/<fpc>/pfe/<pfe>/cm/<cm>/HostLoopback/<cm>/HOSTLOOPBACKMAKECMERRORID[<id>]) This issue affects Juniper Networks Junos OS:
All versions earlier than 20.4R3-S8; 21.1 versions earlier than 21.1R3-S4; 21.2 versions earlier than 21.2R3-S6; 21.3 versions earlier than 21.3R3-S3; 21.4 versions earlier than 21.4R3-S5; 22.1 versions earlier than 22.1R2-S2, 22.1R3; 22.2 versions earlier than 22.2R2-S1, 22.2R3.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
Juniper Networks Junos OS (PTX Series)to a version that resolves this vulnerability.Fixed in 20.4R3-S8 - Upgrade
Upgrade
Juniper Networks Junos OS (PTX Series)to a version that resolves this vulnerability.Fixed in 21.1R3-S4 - Upgrade
Upgrade
Juniper Networks Junos OS (PTX Series)to a version that resolves this vulnerability.Fixed in 21.2R3-S6 - Upgrade
Upgrade
Juniper Networks Junos OS (PTX Series)to a version that resolves this vulnerability.Fixed in 21.3R3-S3 - Upgrade
Upgrade
Juniper Networks Junos OS (PTX Series)to a version that resolves this vulnerability.Fixed in 21.4R3-S5 - Upgrade
Upgrade
Juniper Networks Junos OS (PTX Series)to a version that resolves this vulnerability.Fixed in 22.1R2-S2 - Upgrade
Upgrade
Juniper Networks Junos OS (PTX Series)to a version that resolves this vulnerability.Fixed in 22.1R3 - Upgrade
Upgrade
Juniper Networks Junos OS (PTX Series)to a version that resolves this vulnerability.Fixed in 22.2R2-S1 - Upgrade
Upgrade
Juniper Networks Junos OS (PTX Series)to a version that resolves this vulnerability.Fixed in 22.2R3 - Upgrade
Upgrade
Juniper Networks Junos OS (PTX Series)to a version that resolves this vulnerability.Fixed in 22.3R1 - Compensating control
Avoid having MPLS traffic hit reject next-hop while using a flexible tunnel interface (FTI); the issue occurs when “FTI tunnel is down” and packets hit the reject NH, causing packets to be sent to the CPU and a host path wedge condition.
- Operational
If the FPC hangs due to the host path wedge condition, perform a manual restart to recover (issue states it “requires a manual restart to recover”).
Event History
Frequently Asked Questions
What is the severity of CVE-2024-21600?
The severity of CVE-2024-21600 is rated as high, as it allows for a Denial of Service by an unauthenticated, adjacent attacker.
How do I fix CVE-2024-21600?
To mitigate CVE-2024-21600, update your Junos OS to the latest patched version provided by Juniper Networks.
Which versions of Junos OS are affected by CVE-2024-21600?
CVE-2024-21600 affects Junos OS versions 20.4, 21.1, 21.2, 21.3, 21.4, 22.1, and 22.2.
Who can exploit CVE-2024-21600?
CVE-2024-21600 can be exploited by an unauthenticated, adjacent attacker.
What impact does CVE-2024-21600 have on systems?
The impact of CVE-2024-21600 includes potential Denial of Service, leading to disruption of network services.