Due to an Improper Initialization vulnerability in Juniper Networks Junos OS on PTX platforms and QFX10K Series with Paradise (PE) chipset-based line cards, ddos-protection configuration changes made from the CLI will not take effect as expected beyond the default DDoS (Distributed Denial of Service) settings in the Packet Forwarding Engine (PFE). This may cause BFD sessions to flap when a high rate of specific packets are received. Flapping of BFD sessions in turn may impact routing protocols and network stability, leading to a Denial of Service (DoS) condition. Continued receipt and processing of this packet will create a sustained Denial of Service (DoS) condition.

This issue affects only the following platforms with Paradise (PE) chipset-based line cards:

PTX1000, PTX3000 (NextGen), PTX5000, PTX10008, PTX10016 Series and QFX10002 Series.

This issue affects:

Juniper Networks Junos OS

• 17.4 versions prior to 17.4R3-S5 on PTX Series, QFX10K Series;
• 18.2 versions prior to 18.2R3-S8 on PTX Series, QFX10K Series;
• 18.3 versions prior to 18.3R3-S5 on PTX Series, QFX10K Series;
• 18.4 versions prior to 18.4R2-S8 on PTX Series, QFX10K Series;
• 19.1 versions prior to 19.1R3-S5 on PTX Series, QFX10K Series;
• 19.2 versions prior to 19.2R3-S2 on PTX Series, QFX10K Series;
• 19.3 versions prior to 19.3R3-S2 on PTX Series, QFX10K Series;
• 19.4 versions prior to 19.4R3-S2 on PTX Series, QFX10K Series;
• 20.1 versions prior to 20.1R3 on PTX Series, QFX10K Series;
• 20.2 versions prior to 20.2R2-S3, 20.2R3 on PTX Series, QFX10K Series;
• 20.3 versions prior to 20.3R2 on PTX Series, QFX10K Series;
• 20.4 versions prior to 20.4R2 on PTX Series, QFX10K Series.

The examples of the config stanza affected by this issue:

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

This issue was seen during production usage.

This issue has been assigned CVE-2021-0280 .
 

The following software releases have been updated to resolve this specific issue: Junos OS 17.4R3-S5, 18.2R3-S8, 18.3R3-S5, 18.4R2-S8, 19.1R3-S5, 19.2R3-S2, 19.3R3-S2, 19.4R3-S2, 20.1R3, 20.2R2-S3, 20.2R3, 20.3R2, 20.4R2, 21.1R1, and all subsequent releases.

This issue is being tracked as 1564807 .
 

Software releases or updates are available for download at https://support.juniper.net/support/downloads/
 

The default ukern policer rate can be reduced by the CLI command:

2021-07-14: Initial Publication.

• KB16613: Overview of the Juniper Networks SIRT Quarterly Security Bulletin Publication Process [juniper.net]
• KB16765: In which releases are vulnerabilities fixed? [juniper.net]
• KB16446: Common Vulnerability Scoring System (CVSS) and Juniper's Security Advisories [juniper.net]
• Report a Vulnerability - How to Contact the Juniper Networks Security Incident Response Team
• CVE-2021-0280: Upon receipt of specific packets BFD sessions might flap due to DDoS policer implementation in Packet Forwarding Engine