On Juniper Networks Junos OS devices configured with DHCPv6 relay enabled, receipt of a specific DHCPv6 packet might crash the jdhcpd daemon.

The jdhcpd daemon automatically restarts without intervention, but continuous receipt of specific crafted DHCP messages will repeatedly crash jdhcpd, leading to an extended Denial of Service (DoS) condition.

Only DHCPv6 packet can trigger this issue. DHCPv4 packet cannot trigger this issue.
 

This issue affects Juniper Networks Junos OS:

• 17.3 versions prior to 17.3R3-S9;
• 17.4 versions prior to 17.4R2-S11, 17.4R3-S2, 17.4R3-S3;
• 18.1 versions prior to 18.1R3-S11;
• 18.2 versions prior to 18.2R3-S5;
• 18.3 versions prior to 18.3R2-S4, 18.3R3-S3;
• 18.4 versions prior to 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, 19.2R2-S1, 19.2R3;
• 19.3 versions prior to 19.3R2-S4, 19.3R2-S4, 19.3R3;
• 19.4 versions prior to 19.4R1-S3, 19.4R2-S1, 19.4R3;
• 20.1 versions prior to 20.1R1-S3, 20.1R2.
   

The example 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-2020-1672 .

The following software releases have been updated to resolve this specific issue: Junos OS 17.3R3-S9, 17.4R2-S11, 17.4R3-S2, 17.4R3-S3, 18.1R3-S11, 18.2R3-S5, 18.2X75-D34, 18.2X75-D65, 18.3R2-S4, 18.3R3-S3, 18.4R2-S5, 18.4R3-S4, 19.1R2-S2, 19.1R3-S2, 19.2R1-S5, 19.2R3, 19.3R2-S4, 19.3R3, 19.4R1-S3, 19.4R2-S1, 19.4R3, 20.1R1-S3, 20.1R2, 20.2R1, 20.3X75-D10, and all subsequent releases.

This issue is being tracked as 1512765 .

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

There are no viable workarounds for this issue.

• 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-2020-1672 at cve.mitre.org