An improper input validation vulnerability in the Routing Protocol Daemon (RPD) service of Juniper Networks Junos OS allows an attacker to send a malformed RSVP packet when bidirectional LSPs are in use, which when received by an egress router crashes the RPD causing a Denial of Service (DoS) condition. Continued receipt of the packet will sustain the Denial of Service.

This issue affects:

Juniper Networks Junos OS:

• All versions prior to 17.3R3-S10 except 15.1X49-D240 for SRX series;
• 17.4 versions prior to 17.4R3-S2;
• 18.1 versions prior to 18.1R3-S10;
• 18.2 versions prior to 18.2R2-S7, 18.2R3-S4;
• 18.3 versions prior to 18.3R3-S2;
• 18.4 versions prior to 18.4R1-S8, 18.4R2-S6, 18.4R3-S2;
• 19.1 versions prior to 19.1R1-S5, 19.1R3-S3;
• 19.2 versions prior to 19.2R3;
• 19.3 versions prior to 19.3R2-S5, 19.3R3;
• 19.4 versions prior to 19.4R2-S2, 19.4R3-S1;
• 20.1 versions prior to 20.1R1-S4, 20.1R2;
• 15.1X49 versions prior to 15.1X49-D240 on SRX Series.

Juniper Networks Junos OS Evolved:

• 19.3 versions prior to 19.3R2-S5-EVO;
• 19.4 versions prior to 19.4R2-S2-EVO;
• 20.1 versions prior to 20.1R1-S4-EVO.

The following are examples of minimal configurations:

or

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-2021-0208 .

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

Junos OS: 15.1X49-D240, 17.3R3-S10, 17.4R3-S2, 18.1R3-S10, 18.2R2-S7, 18.2R3-S4, 18.3R3-S2, 18.4R1-S8, 18.4R2-S6, 18.4R3-S2, 19.1R1-S5, 19.1R3-S3, 19.2R3, 19.3R2-S5, 19.3R3, 19.4R2-S2, 19.4R3-S1, 20.1R1-S4, 20.1R2, 20.2R1, and all subsequent releases.

Note: With the exception of SRX Series products using version 15.1X49-D240, all products using Junos OS prior to 17.3R3-S10 are affected and will not be fixed by Juniper Networks, Inc.

Junos OS Evolved: 19.3R2-S5-EVO, 19.4R2-S2-EVO, 20.1R1-S4-EVO, and all subsequent releases.

This issue is being tracked as  1493718 .

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

If bidirectional LSPs are running in the network, when changing family mpls maximum-labels on an interface, first disable RSVP for this interface.

You can include the disable statement at the following hierarchy levels:

See the MPLS RSVP disable configuration guide for further details.

• 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 Security Vulnerability - How to Contact the Juniper Networks Security Incident Response Team
• CVE-2021-0208 at cve.mitre.org
• https://www.juniper.net/documentation/en_US/junos/topics/reference/configuration-statement/disable-edit-protocols-rsvp.html
• https://www.juniper.net/documentation/en_US/junos/topics/reference/configuration-statement/corouted-bidirectional-edit-protocols-mpls.html