An Improper Input Validation vulnerability in J-Web of Juniper Networks Junos OS allows a locally authenticated attacker to escalate their privileges to root over the target device.

junos:18.3R3-S5 junos:18.4R3-S9 junos:19.1R3-S6 junos:19.3R2-S6 junos:19.3R3-S3 junos:19.4R1-S4 junos:19.4R3-S4 junos:20.1R2-S2 junos:20.1R3 junos:20.2R3-S1 junos:20.3X75-D20 junos:20.3X75-D30 junos:20.4R2-S1 junos:20.4R3 junos:21.1R1-S1 junos:21.1R2 junos:21.2R1 junos:21.3R1

This issue affects:

Juniper Networks Junos OS

19.3 versions 19.3R1 and above prior to 19.3R2-S6, 19.3R3-S3;

19.4 versions prior to 19.4R3-S5;

20.1 versions prior to 20.1R2-S2, 20.1R3-S1;

20.2 versions prior to 20.2R3-S2;

20.3 versions prior to 20.3R3;

20.4 versions prior to 20.4R2-S1, 20.4R3;

21.1 versions prior to 21.1R1-S1, 21.1R2.

This issue does not affect Juniper Networks Junos OS versions prior to 19.3R1.

The following minimal configuration is necessary:

or

Juniper SIRT is not aware of any malicious exploitation of this vulnerability. However, a proof-of-concept exploit does exist in the wild.

This issue was seen during production usage.

This issue has been assigned  CVE-2021-0278 .

The following software releases have been updated to resolve this specific issue: 19.3R2-S6, 19.3R3-S3, 19.4R3-S5, 20.1R2-S2, 20.1R3-S1, 20.2R3-S2, 20.3R3, 20.4R2-S1, 20.4R3, 21.1R1-S1, 21.1R2, 21.2R1, and all subsequent releases.

In addition to the above fixed releases, for the following not-affected releases additional security enhancements were included in Junos OS 18.3R3-S5, 18.4R3-S9, 19.1R3-S6 as a result of resolving this issue.

This issue is being tracked as  1592021  and  1511853 .

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

There are no viable workarounds for this issue other than disabling J-Web.

To reduce the risk of exploitation of these issues, use access lists or firewall filters to limit access to only trusted administrative networks, hosts and users.

2021-07-14: 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 Vulnerability - How to Contact the Juniper Networks Security Incident Response Team
• CVE-2021-0278: Junos OS: J-Web allows a locally authenticated attacker to escalate their privileges to root.

The Juniper SIRT wishes to thank Luca Ercoli regarding PR 1511853