An improper authorization vulnerability in the Simple Network Management Protocol daemon (snmpd) service of Juniper Networks Junos OS leads an unauthenticated attacker being able to perform SNMP read actions, an Exposure of System Data to an Unauthorized Control Sphere, or write actions to OIDs that support write operations, against the device without authentication.

This issue affects:

Juniper Networks Junos OS:

• 17.2 version 17.2R1 and later versions;
• 17.3 versions prior to 17.3R3-S9;
• 17.4 versions prior to 17.4R2-S12, 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-S5, 18.4R3;
• 19.1 versions prior to 19.1R2;
• 19.2 versions prior to 19.2R1-S6, 19.2R2;
• 19.3 versions prior to 19.3R2.

• This issue does not affect Juniper Networks Junos OS versions prior to 17.2R1.

Devices configured with any version of SNMP, regardless of configuration statements or authentication methods are vulnerable to this issue.

If the following minimal configuration is present, the device is vulnerable to exploitation:

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-2021-0260 .

The following software releases have been updated to resolve this specific issue: 17.3R3-S9, 17.4R2-S12, 17.4R3-S5, 18.1R3-S13, 18.2R3-S8, 18.3R3-S5, 18.4R1-S8, 18.4R2-S5, 18.4R3, 19.1R2, 19.2R1-S6, 19.2R2, 19.3R2, 19.4R1, and all subsequent releases.

This issue is being tracked as  1458057 .

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

The following workaround command will disable SNMP support for the mgmt_junos routing interface and protect the device from being exploited:

2021-04-14: 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 Security Vulnerability - How to Contact the Juniper Networks Security Incident Response Team
• CVE-2021-0260 at cve.mitre.org