title: Junos OS: PTX Series, QFX10K Series: A PTX/QFX FPC may restart unexpectedly with the "inline-Jflow" feature enabled on a large-scale deployment
description: 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 of large traffic flows and reconvergence-like situations may sustain the Denial of Service (DoS) situation. This issue affects: Juniper Networks Junos OS: 18.1 version 18.1R2 and later versions prior to 18.1R3-S10 on PTX Series, QFX10K Series.
problem types: CWE-362 Race Condition (Concurrent Execution using Shared Resource with Improper Synchronization)
affected:
{
platforms: PTX Series, QFX10K Series
product: Junos OS
vendor: Juniper Networks
versions:
changes: [at: 18.1R3-S10, status: affected], lessThan: 18.1*, status: affected, version: 18.1R2, versionType: custom
}
metrics:
cvssV3_1: [
attackComplexity: LOW
attackVector: NETWORK
availabilityImpact: HIGH
baseScore: 7.5
baseSeverity: HIGH
confidentialityImpact: NONE
integrityImpact: NONE
privilegesRequired: NONE
scope: UNCHANGED
userInteraction: NONE
vectorString: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
version: 3.1
]
exploits: Juniper SIRT is not aware of any malicious exploitation of this vulnerability.
solutions: 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.
workarounds: 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.