CVE-2021-31350

Junos OS and Junos OS Evolved: Privilege escalation vulnerability in Juniper Extension Toolkit (JET)

Description

An Improper Privilege Management vulnerability in the gRPC framework, used by the Juniper Extension Toolkit (JET) API on Juniper Networks Junos OS and Junos OS Evolved, allows a network-based, low-privileged authenticated attacker to perform operations as root, leading to complete compromise of the targeted system. The issue is caused by the JET service daemon (jsd) process authenticating the user, then passing configuration operations directly to the management daemon (mgd) process, which runs as root. This issue affects Juniper Networks Junos OS: 18.4 versions prior to 18.4R1-S8, 18.4R2-S8, 18.4R3-S8; 19.1 versions prior to 19.1R2-S3, 19.1R3-S5; 19.2 versions prior to 19.2R1-S7, 19.2R3-S2; 19.3 versions prior to 19.3R2-S6, 19.3R3-S2; 19.4 versions prior to 19.4R1-S4, 19.4R2-S4, 19.4R3-S3; 20.1 versions prior to 20.1R2-S2, 20.1R3; 20.2 versions prior to 20.2R2-S3, 20.2R3; 20.3 versions prior to 20.3R2-S1, 20.3R3; 20.4 versions prior to 20.4R2. This issue does not affect Juniper Networks Junos OS versions prior to 18.4R1. Juniper Networks Junos OS Evolved: All versions prior to 20.4R2-EVO; 21.1-EVO versions prior to 21.1R2-EVO.

Remediation

Solution:

  • The following software releases have been updated to resolve this specific issue: Junos OS 18.4R1-S8, 18.4R2-S8, 18.4R3-S8, 19.1R2-S3, 19.1R3-S5, 19.2R1-S7, 19.2R3-S2, 19.3R2-S6, 19.3R3-S2, 19.4R1-S4, 19.4R2-S4, 19.4R3-S3, 20.1R2-S2, 20.1R3, 20.2R2-S3, 20.2R3, 20.3R2-S1, 20.3R3, 20.4R2, 21.1R1, and all subsequent releases. Junos OS Evolved 20.4R2-EVO, 21.1R2-EVO, 21.2R1-EVO, and all subsequent releases.

Workaround:

  • Use access lists or firewall filters to limit access to the device via gRPC only from trusted hosts and from trusted administrators

Category

7.5
CVSS
Severity: High
CVSS 3.1 •
CVSS 2.0 •
EPSS 0.34%
Vendor Advisory juniper.net
Affected: Juniper Networks Junos OS
Affected: Juniper Networks Junos OS Evolved
Published at:
Updated at:

References

Link Tags
https://kb.juniper.net/JSA11215 patch vendor advisory

Frequently Asked Questions

What is the severity of CVE-2021-31350?
CVE-2021-31350 has been scored as a high severity vulnerability.
How to fix CVE-2021-31350?
To fix CVE-2021-31350: The following software releases have been updated to resolve this specific issue: Junos OS 18.4R1-S8, 18.4R2-S8, 18.4R3-S8, 19.1R2-S3, 19.1R3-S5, 19.2R1-S7, 19.2R3-S2, 19.3R2-S6, 19.3R3-S2, 19.4R1-S4, 19.4R2-S4, 19.4R3-S3, 20.1R2-S2, 20.1R3, 20.2R2-S3, 20.2R3, 20.3R2-S1, 20.3R3, 20.4R2, 21.1R1, and all subsequent releases. Junos OS Evolved 20.4R2-EVO, 21.1R2-EVO, 21.2R1-EVO, and all subsequent releases.
Is CVE-2021-31350 being actively exploited in the wild?
As for now, there are no information to confirm that CVE-2021-31350 is being actively exploited. According to its EPSS score, there is a ~0% probability that this vulnerability will be exploited by malicious actors in the next 30 days.
What software or system is affected by CVE-2021-31350?
CVE-2021-31350 affects Juniper Networks Junos OS, Juniper Networks Junos OS Evolved.
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