CVE-2021-31356

Junos OS Evolved: Multiple shell-injection vulnerabilities in EVO UI wrapper scripts

Description

A command injection vulnerability in command processing on Juniper Networks Junos OS Evolved allows an attacker with authenticated CLI access to be able to bypass configured access protections to execute arbitrary shell commands within the context of the current user. The vulnerability allows an attacker to bypass command authorization restrictions assigned to their specific user account and execute commands that are available to the privilege level for which the user is assigned. For example, a user that is in the super-user login class, but restricted to executing specific CLI commands could exploit the vulnerability to execute any other command available to an unrestricted admin user. This vulnerability does not increase the privilege level of the user, but rather bypasses any CLI command restrictions by allowing full access to the shell. This issue affects Juniper Networks Junos OS Evolved: All versions prior to 20.4R3-S1-EVO; All versions of 21.1-EVO and 21.2-EVO.

Remediation

Solution:

  • The following software releases have been updated to resolve this specific issue: Junos OS Evolved 20.4R3-S1-EVO*, 21.3R1-EVO, and all subsequent releases. *Late availability

Workaround:

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

Categories

7.8
CVSS
Severity: High
CVSS 3.1 •
CVSS 2.0 •
EPSS 0.42%
Vendor Advisory juniper.net
Affected: Juniper Networks Junos OS Evolved
Published at:
Updated at:

References

Link Tags
https://kb.juniper.net/JSA11221 vendor advisory

Frequently Asked Questions

What is the severity of CVE-2021-31356?
CVE-2021-31356 has been scored as a high severity vulnerability.
How to fix CVE-2021-31356?
To fix CVE-2021-31356: The following software releases have been updated to resolve this specific issue: Junos OS Evolved 20.4R3-S1-EVO*, 21.3R1-EVO, and all subsequent releases. *Late availability
Is CVE-2021-31356 being actively exploited in the wild?
As for now, there are no information to confirm that CVE-2021-31356 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-2021-31356?
CVE-2021-31356 affects Juniper Networks Junos OS Evolved.
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