In Juniper Networks Junos OS Evolved an attacker sending certain valid BGP update packets may cause Junos OS Evolved to access an uninitialized pointer causing RPD to core leading to a Denial of Service (DoS).

Continued receipt of these types of valid BGP update packets will cause an extended Denial of Service condition.

RPD will require a restart to recover.

An indicator of compromise is to see if the file rpd.re exists by issuing the command:

This issue affects:

Juniper Networks Junos OS Evolved

• 19.4 versions prior to 19.4R2-S2-EVO;
• 20.1 versions prior to 20.1R1-S2-EVO, 20.1R2-S1-EVO.

This issue does not affect Junos OS.

The following minimal configuration which will vary by implementation is necessary:

• Must be running Junos OS Evolved
• A BGP peering session is configured.
• Regular expressions (REGEX) are being used with BGP.

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-2021-0209 .

The following software releases have been updated to resolve this specific issue: Junos OS Evolved: 19.4R2-S2-EVO, 20.1R1-S2-EVO, 20.1R2-S1-EVO, 20.2R1-EVO and all subsequent releases.

This issue is being tracked as  1517128 .

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

• 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-2021-0209 at cve.mitre.org