CVE-2021-31386

Junos OS: When using J-Web with HTTP an attacker may retrieve encryption keys via Person-in-the-Middle attacks.

Published Oct 19, 2021 CVSS 3.1 · 5.3 Medium EPSS < 1% KEV · Not listed
Description
A Protection Mechanism Failure vulnerability in the J-Web HTTP service of Juniper Networks Junos OS allows a remote unauthenticated attacker to perform Person-in-the-Middle (PitM) attacks against the device. This issue affects: Juniper Networks Junos OS 12.3 versions prior to 12.3R12-S20; 15.1 versions prior to 15.1R7-S11; 18.3 versions prior to 18.3R3-S6; 18.4 versions prior to 18.4R3-S10; 19.1 versions prior to 19.1R3-S7; 19.2 versions prior to 19.2R3-S4; 19.3 versions prior to 19.3R3-S4; 19.4 versions prior to 19.4R3-S6; 20.1 versions prior to 20.1R3-S2; 20.2 versions prior to 20.2R3-S3; 20.3 versions prior to 20.3R3-S1; 20.4 versions prior to 20.4R3; 21.1 versions prior to 21.1R3; 21.2 versions prior to 21.2R2.

Remediation

Vendor Solution

The following software releases have been updated to resolve this specific issue: 12.3R12-S20, 15.1R7-S11, 18.3R3-S6, 18.4R3-S10, 19.1R3-S7, 19.2R3-S4, 19.3R3-S4, 19.4R3-S6, 20.1R3-S2, 20.2R3-S3, 20.3R3-S1, 20.4R3, 21.1R3, 21.2R2, 21.3R1, and all subsequent releases. Note: Use of HTTP must also be discontinued.


Vendor Workaround

Discontinue the use of HTTP, instead use HTTPS when using J-Web. [system services web-management https]

Tracking

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Advisories

Source ID Title
EUVD EUVD EUVD-2021-18296 A Protection Mechanism Failure vulnerability in the J-Web HTTP service of Juniper Networks Junos OS allows a remote unauthenticated attacker to perform Person-in-the-Middle (PitM) attacks against the device. This issue affects: Juniper Networks Junos OS 12.3 versions prior to 12.3R12-S20; 15.1 versions prior to 15.1R7-S11; 18.3 versions prior to 18.3R3-S6; 18.4 versions prior to 18.4R3-S10; 19.1 versions prior to 19.1R3-S7; 19.2 versions prior to 19.2R3-S4; 19.3 versions prior to 19.3R3-S4; 19.4 versions prior to 19.4R3-S6; 20.1 versions prior to 20.1R3-S2; 20.2 versions prior to 20.2R3-S3; 20.3 versions prior to 20.3R3-S1; 20.4 versions prior to 20.4R3; 21.1 versions prior to 21.1R3; 21.2 versions prior to 21.2R2.
References
History

No history.

Sources

Status
PUBLISHED
Assigner
juniper
Published
Updated
Sep 17, 2024, 1:16 AM
Reserved
Apr 15, 2021, 12:00 AM
Status
Modified
Published
Oct 19, 2021, 7:15 PM
Modified
Jun 17, 2026, 3:51 AM