title: Junos OS Evolved: Incorrect file permissions can allow low-privileged user to cause another user to execute arbitrary commands
description: An Incorrect Permission Assignment vulnerability in shell processing of Juniper Networks Junos OS Evolved allows a low-privileged local user to modify the contents of a configuration file which could cause another user to execute arbitrary commands within the context of the follow-on user's session. If the follow-on user is a high-privileged administrator, the attacker could leverage this vulnerability to take complete control of the target system. While this issue is triggered by a user, other than the attacker, accessing the Junos shell, an attacker simply requires Junos CLI access to exploit this vulnerability. This issue affects Juniper Networks Junos OS Evolved: 20.4-EVO versions prior to 20.4R3-S1-EVO; All versions of 21.1-EVO; 21.2-EVO versions prior to 21.2R3-EVO; 21.3-EVO versions prior to 21.3R2-EVO. This issue does not affect Juniper Networks Junos OS Evolved versions prior to 19.2R1-EVO.
problem types: CWE-732 Incorrect Permission Assignment for Critical Resource
affected:
{
vendor: Juniper Networks
product: Junos OS Evolved
versions:
version: unspecified, lessThan: 19.2R1-EVO, status: unaffected, versionType: custom
version: 20.4-EVO, status: affected, lessThan: 20.4R3-S1-EVO, versionType: custom
version: 21.1R1-EVO, status: affected, lessThan: 21.1-EVO*, versionType: custom
version: 21.2-EVO, status: affected, lessThan: 21.2R3-EVO, versionType: custom
version: 21.3-EVO, status: affected, lessThan: 21.3R2-EVO, versionType: custom
}
metrics:
cvssV3_1: [
version: 3.1
vectorString: CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H
attackVector: LOCAL
attackComplexity: LOW
privilegesRequired: LOW
userInteraction: REQUIRED
scope: UNCHANGED
confidentialityImpact: HIGH
integrityImpact: HIGH
availabilityImpact: HIGH
baseScore: 7.3
baseSeverity: HIGH
]
exploits: Juniper SIRT is not aware of any malicious exploitation of this vulnerability.
solutions: The following software releases have been updated to resolve this specific issue: Junos OS Evolved 20.4R3-S1-EVO, 21.2R3-EVO, 21.3R2-EVO, 21.4R1-EVO, and all subsequent releases.
workarounds: Limit access to the Junos shell by system administrators until an upgrade can be performed.
Use access lists or firewall filters to limit access to the Junos CLI only from trusted hosts and administrators.