title: Junos OS and Junos OS Evolved: Denial of Service vulnerability in local file processing
description: An improper privilege management vulnerability in the Juniper Networks Junos OS and Junos OS Evolved command-line interpreter (CLI) allows a low-privileged user to overwrite local files as root, possibly leading to a system integrity issue or Denial of Service (DoS). Depending on the files overwritten, exploitation of this vulnerability could lead to a sustained Denial of Service (DoS) condition, requiring manual user intervention to recover. Systems are only vulnerable if jdhcpd is running, which can be confirmed via the 'show system processes' command. For example: root@host# run show system processes extensive | match dhcp 26537 root -16 0 97568K 13692K RUN 0 0:01 3.71% jdhcpd This issue affects: Juniper Networks Junos OS: All versions, including the following supported releases: 15.1 versions prior to 15.1R7-S10; 17.4 versions prior to 17.4R3-S5; 18.3 versions prior to 18.3R3-S5; 18.4 versions prior to 18.4R3-S9; 19.1 versions prior to 19.1R3-S6; 19.2 versions prior to 19.2R1-S7, 19.2R3-S3; 19.3 versions prior to 19.3R2-S6, 19.3R3-S3; 19.4 versions prior to 19.4R3-S6; 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. Juniper Networks Junos OS Evolved: All versions prior to 20.4R2-S3-EVO; All versions of 21.1-EVO.
problem types: CWE-269 Improper Privilege Management
affected:
{
product: Junos OS
vendor: Juniper Networks
versions:
lessThan: 15.1R7-S10, status: affected, version: 15.1, versionType: custom
lessThan: 17.4R3-S5, status: affected, version: 17.4, versionType: custom
lessThan: 18.3R3-S5, status: affected, version: 18.3, versionType: custom
lessThan: 18.4R3-S9, status: affected, version: 18.4, versionType: custom
lessThan: 19.1R3-S6, status: affected, version: 19.1, versionType: custom
lessThan: 19.2R1-S7, 19.2R3-S3, status: affected, version: 19.2, versionType: custom
lessThan: 19.3R2-S6, 19.3R3-S3, status: affected, version: 19.3, versionType: custom
lessThan: 19.4R3-S6, status: affected, version: 19.4, versionType: custom
lessThan: 20.1R2-S2, 20.1R3-S1, status: affected, version: 20.1, versionType: custom
lessThan: 20.2R3-S2, status: affected, version: 20.2, versionType: custom
lessThan: 20.3R3, status: affected, version: 20.3, versionType: custom
lessThan: 20.4R2-S1, 20.4R3, status: affected, version: 20.4, versionType: custom
lessThan: 21.1R1-S1, 21.1R2, status: affected, version: 21.1, versionType: custom
}
{
product: Junos OS Evolved
vendor: Juniper Networks
versions:
lessThan: 20.4R2-S3-EVO, status: affected, version: unspecified, versionType: custom
lessThan: 21.1*, status: affected, version: 21.1R1-EVO, versionType: custom
}
metrics:
cvssV3_1: [
attackComplexity: LOW
attackVector: LOCAL
availabilityImpact: HIGH
baseScore: 7.1
baseSeverity: HIGH
confidentialityImpact: NONE
integrityImpact: HIGH
privilegesRequired: LOW
scope: UNCHANGED
userInteraction: NONE
vectorString: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H
version: 3.1
]
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 15.1R7-S10, 17.4R3-S5, 18.3R3-S5, 18.4R3-S9, 19.1R3-S6, 19.2R1-S7, 19.2R3-S3, 19.3R2-S6, 19.3R3-S3, 19.4R3-S6, 20.1R2-S2, 20.1R3-S1, 20.2R3-S2, 20.3R3, 20.4R2-S1, 20.4R3, 21.1R1-S1, 21.1R2, 21.1R3, 21.2R1, and all subsequent releases.
Junos OS Evolved 20.4R2-S3-EVO, 21.2R1-EVO, and all subsequent releases.
workarounds: Use access lists or firewall filters to limit access to the device via CLI only from trusted hosts and from trusted administrators.