On PTX1000 System, PTX10002-60C System, after upgrading to an affected release, a Race Condition vulnerability between the chassis daemon (chassisd) and firewall process (dfwd) of Juniper Networks Junos OS, may update the device's interfaces with incorrect firewall filters. This issue only occurs when upgrading the device to an affected version of Junos OS.

Interfaces intended to have protections may have no protections assigned to them. Interfaces with one type of protection pattern may have alternate protections assigned to them. Interfaces intended to have no protections may have protections assigned to them.

These firewall rule misassignments may allow genuine traffic intended to be stopped at the interface to propagate further, potentially causing disruptions in services by propagating unwanted traffic. An attacker may be able to take advantage of these misassignments.

This issue affects Juniper Networks Junos OS on PTX1000 System:

• 17.2 versions 17.2R1 and later versions prior to 17.3 versions prior to 17.3R3-S12;
• 17.4 versions prior to 17.4R3-S5;
• 18.1 versions prior to 18.1R3-S13;
• 18.2 versions prior to 18.2R3-S8;
• 18.3 versions prior to 18.3R3-S5;
• 18.4 versions prior to 18.4R1-S8, 18.4R2-S8, 18.4R3-S8;
• 19.1 versions prior to 19.1R3-S5;
• 19.2 versions prior to 19.2R3-S2;
• 19.3 versions prior to 19.3R2-S6, 19.3R3-S3;
• 19.4 versions prior to 19.4R2-S4, 19.4R3-S3;
• 20.1 versions prior to 20.1R3;
• 20.2 versions prior to 20.2R2-S3, 20.2R3;
• 20.3 versions prior to 20.3R2-S1, 20.3R3;
• 20.4 versions prior to 20.4R1-S1, 20.4R2.

This issue does not affect Juniper Networks Junos OS prior to version 17.2R1 on PTX1000 System.

This issue affects Juniper Networks Junos OS on PTX10002-60C System:

• 18.2 versions 18.2R1 and later versions prior to 18.4 versions prior to 18.4R3-S9;
• 19.1 versions later than 19.1R1 prior to 19.4 versions prior to 19.4R2-S5, 19.4R3-S5;
• 20.1 versions prior to 20.1R3-S1;
• 20.2 versions prior to 20.2R3-S2;
• 20.3 versions prior to 20.3R3-S1;
• 20.4 versions 20.4R1 and later versions prior to 21.1 versions prior to 21.1R2;
• 21.2 versions 21.2R1 and later versions prior to 21.3 versions prior to 21.3R2.

This issue does not affect Juniper Networks Junos OS prior to version 18.2R1 on PTX10002-60C System.

This issue impacts all filter families (inet, inet6, etc.) and all loopback filters.

It does not rely upon the location where a filter is set, impacting both logical and physical interfaces.

Configuration examples for firewall filtering are posted on the support site and in the product documentation.

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-2021-31382 .

The following software releases have been updated to resolve this specific issue:

Junos OS on PTX1000 System: 17.3R3-S12, 18.1R3-S13, 18.2R3-S8, 18.3R3-S5, 18.4R1-S8, 18.4R2-S8, 18.4R3-S8, 19.1R3-S5, 19.2R3-S2, 19.3R2-S6, 19.3R3-S3, 19.4R2-S4, 19.4R3-S3, 20.1R3, 20.2R2-S3, 20.2R3, 20.3R2-S1, 20.3R3, 20.4R1-S1, 20.4R2, 21.1R1, and all subsequent releases.

Junos OS on PTX10002-60C System: 18.4R3-S9, 19.4R2-S5, 19.4R3-S5, 20.1R3-S1, 20.2R3-S2, 20.3R3-S1, 21.1R2, 21.3R2, 21.4R1, and all subsequent releases.

This issue is being tracked as  1517804  and  1602292 .

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

Restart the firewall daemon after the system has rebooted after the upgrade.

2021-10-13: 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-2021-31382 at cve.mitre.org
• [Junos] How to restart a specific process in Junos?