CVE-2020-1679: Junos OS: PTX/QFX Series: Kernel Routing Table (KRT) queue stuck after packet sampling a malformed packet when the tunnel-observation mpls-over-udp configuration is enabled.
On Juniper Networks PTX and QFX Series devices with packet sampling configured using tunnel-observation mpls-over-udp, sampling of a malformed packet can cause the Kernel Routing Table (KRT) queue to become stuck. KRT is the module within the Routing Process Daemon (RPD) that synchronized the routing tables with the forwarding tables in the kernel. This table is then synchronized to the Packet Forwarding Engine (PFE) via the KRT queue. Thus, when KRT queue become stuck, it can lead to unexpected packet forwarding issues. An administrator can monitor the following command to check if there is the KRT queue is stuck: user@device > show krt state ... Number of async queue entries: 65007 <--- this value keep on increasing. When this issue occurs, the following message might appear in the /var/log/messages: DATE DEVICE kernel: %KERN-3: rtpfeveto: Too many delayed route/nexthop unrefs. Op 2 err 55, rtsmid 5:-1, msg type 2 DATE DEVICE kernel: %KERN-3: rtpfeveto: Memory usage of MRTNEXTHOP type = (0) Max size possible for MRTNEXTHOP type = (7297134592) Current delayed unref = (60000), Current unique delayed unref = (18420), Max delayed unref on this platform = (40000) Current delayed weight unref = (60000) Max delayed weight unref on this platform= (400000) curproc = rpd This issue affects Juniper Networks Junos OS on PTX/QFX Series: 17.2X75 versions prior to 17.2X75-D105; 18.1 versions prior to 18.1R3-S11; 18.2 versions prior to 18.2R3-S5; 18.2X75 versions prior to 18.2X75-D420, 18.2X75-D53, 18.2X75-D65; 18.3 versions prior to 18.3R2-S4, 18.3R3-S3; 18.4 versions prior to 18.4R1-S7, 18.4R2-S5, 18.4R3-S4; 19.1 versions prior to 19.1R2-S2, 19.1R3-S2; 19.2 versions prior to 19.2R1-S5, 19.2R3; 19.3 versions prior to 19.3R2-S3, 19.3R3; 19.4 versions prior to 19.4R1-S2, 19.4R2-S1, 19.4R3; 20.1 versions prior to 20.1R1-S2, 20.1R2. This issue does not affect Juniper Networks Junos OS prior to 18.1R1.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
Juniper Junos OS (PTX/QFX)to a version that resolves this vulnerability.Fixed in 17.2X75-D105 - Upgrade
Upgrade
Juniper Junos OS (PTX/QFX)to a version that resolves this vulnerability.Fixed in 18.1R3-S11 - Upgrade
Upgrade
Juniper Junos OS (PTX/QFX)to a version that resolves this vulnerability.Fixed in 18.2R3-S5 - Upgrade
Upgrade
Juniper Junos OS (PTX/QFX)to a version that resolves this vulnerability.Fixed in 18.2X75-D420 - Upgrade
Upgrade
Juniper Junos OS (PTX/QFX)to a version that resolves this vulnerability.Fixed in 18.2X75-D53 - Upgrade
Upgrade
Juniper Junos OS (PTX/QFX)to a version that resolves this vulnerability.Fixed in 18.2X75-D65 - Upgrade
Upgrade
Juniper Junos OS (PTX/QFX)to a version that resolves this vulnerability.Fixed in 18.3R2-S4 - Upgrade
Upgrade
Juniper Junos OS (PTX/QFX)to a version that resolves this vulnerability.Fixed in 18.3R3-S3 - Upgrade
Upgrade
Juniper Junos OS (PTX/QFX)to a version that resolves this vulnerability.Fixed in 18.4R1-S7 - Upgrade
Upgrade
Juniper Junos OS (PTX/QFX)to a version that resolves this vulnerability.Fixed in 18.4R2-S5 - Upgrade
Upgrade
Juniper Junos OS (PTX/QFX)to a version that resolves this vulnerability.Fixed in 18.4R3-S4 - Upgrade
Upgrade
Juniper Junos OS (PTX/QFX)to a version that resolves this vulnerability.Fixed in 19.1R2-S2 - Upgrade
Upgrade
Juniper Junos OS (PTX/QFX)to a version that resolves this vulnerability.Fixed in 19.1R3-S2 - Upgrade
Upgrade
Juniper Junos OS (PTX/QFX)to a version that resolves this vulnerability.Fixed in 19.2R1-S5 - Upgrade
Upgrade
Juniper Junos OS (PTX/QFX)to a version that resolves this vulnerability.Fixed in 19.2R3 - Upgrade
Upgrade
Juniper Junos OS (PTX/QFX)to a version that resolves this vulnerability.Fixed in 19.3R2-S3 - Upgrade
Upgrade
Juniper Junos OS (PTX/QFX)to a version that resolves this vulnerability.Fixed in 19.3R3 - Upgrade
Upgrade
Juniper Junos OS (PTX/QFX)to a version that resolves this vulnerability.Fixed in 19.4R1-S2 - Upgrade
Upgrade
Juniper Junos OS (PTX/QFX)to a version that resolves this vulnerability.Fixed in 19.4R2-S1 - Upgrade
Upgrade
Juniper Junos OS (PTX/QFX)to a version that resolves this vulnerability.Fixed in 19.4R3 - Upgrade
Upgrade
Juniper Junos OS (PTX/QFX)to a version that resolves this vulnerability.Fixed in 20.1R1-S2 - Upgrade
Upgrade
Juniper Junos OS (PTX/QFX)to a version that resolves this vulnerability.Fixed in 20.1R2 - Upgrade
Upgrade
Juniper Junos OS (PTX/QFX)to a version that resolves this vulnerability.Fixed in 20.2R1 - Upgrade
Upgrade
Juniper Junos OS (PTX/QFX)to a version that resolves this vulnerability.Fixed in 20.3X75-D10 - Configuration
If packet sampling of tunnel-observation mpls-over-udp is enabled and the issue is observed (KRT async queue entries increasing; kernel messages like rt_pfe_veto), disable the tunnel-observation mpls-over-udp configuration as a mitigation while upgrading to a fixed Junos OS release.
Junos OS (tunnel-observation mpls-over-udp) tunnel-observation mpls-over-udp = disabled
Event History
Frequently Asked Questions
What is the severity of CVE-2020-1679?
CVE-2020-1679 is classified as a moderate severity vulnerability due to its potential impact on routing functionality.
How do I fix CVE-2020-1679?
To remediate CVE-2020-1679, it is recommended to upgrade the affected Juniper Networks devices to a patched version of the Junos operating system.
What devices are affected by CVE-2020-1679?
CVE-2020-1679 affects Juniper Networks PTX and QFX Series devices configured with packet sampling using tunnel-observation mpls-over-udp.
What kind of issues does CVE-2020-1679 cause?
CVE-2020-1679 can cause the Kernel Routing Table queue to become stuck when handling malformed packets.
Are there any workarounds for CVE-2020-1679?
Currently, there are no specific workarounds documented for CVE-2020-1679 other than upgrading devices to the latest firmware.