On PTX Series and QFX10k Series devices with the "inline-jflow" feature enabled, a use after free weakness in the Packet Forwarding Engine (PFE) microkernel architecture of Juniper Networks Junos OS may allow an attacker to cause a Denial of Service (DoS) condition whereby one or more Flexible PIC Concentrators (FPCs) may restart. As this is a race condition situation this issue become more likely to be hit when network instability occurs, such as but not limited to BGP/IGP reconvergences, and/or further likely to occur when more active "traffic flows" are occurring through the device. When this issue occurs, it will cause one or more FPCs to restart unexpectedly. During FPC restarts core files will be generated. While the core file is generated traffic will be disrupted. Sustained receipt
The following software releases have been updated to resolve this specific issue: 16.1R7-S8, 17.2R3-S4, 17.3R3-S8, 17.4R2-S11, 17.4R3-S2, 18.1R3-S10, 18.2R1, and all subsequent releases.
If you are susceptible to this issue and unable to upgrade to software with the fix, you can deploy a workaround by disabling the “inline-flow” feature. To check for use and to disable the “inline-jflow” service on a device, see https://www.juniper.net/documentation/en_US/junos/topics/task/configuration/inline-flow-monitoring-ptx.html for additional details. Removing “inline-jflow” takes effect immediately and there is no need to restart the FPCs or the router. Once the feature is removed, the router no longer provides traffic data to the flow collector.
| Product | Vulnerable range | Fixed version | Advisory |
|---|---|---|---|
| Juniper Networks Junos OS | >=18.1R2<18.1* | 18.1* | advisory ↗ |