An Improper Restriction of Operations within the Bounds of a Memory Buffer vulnerability in the management daemon (mgd) process of Juniper Networks Junos OS and Junos OS Evolved allows a network-based authenticated low-privileged attacker, by executing a specific command via NETCONF, to cause a CPU Denial of Service to the device's control plane.

This issue affects:

Juniper Networks Junos OS

• All versions prior to 20.4R3-S7;
• 21.2 versions prior to 21.2R3-S5;
• 21.3 versions prior to 21.3R3-S5;
• 21.4 versions prior to 21.4R3-S4;
• 22.1 versions prior to 22.1R3-S2;
• 22.2 versions prior to 22.2R3;
• 22.3 versions prior to 22.3R2-S1, 22.3R3;
• 22.4 versions prior to 22.4R1-S2, 22.4R2.

Juniper Networks Junos OS Evolved

• All versions prior to 21.4R3-S4-EVO;
• 22.1 versions prior to 22.1R3-S2-EVO;
• 22.2 versions prior to 22.2R3-EVO;
• 22.3 versions prior to 22.3R3-EVO;
• 22.4 versions prior to 22.4R2-EVO.

An indicator of compromise can be seen by first determining if the NETCONF client is logged in and fails to log out after a reasonable period of time and secondly reviewing the WCPU percentage for the mgd process by running the following command:

mgd process example:

Example to check for NETCONF activity:

While there is no specific command that shows a specific session in use for NETCONF, you can review logs for UI_LOG_EVENT with "client-mode 'netconf'"

For example:

Juniper SIRT is not aware of any malicious exploitation of this vulnerability.

This issue was seen during production usage.

This issue has been assigned CVE-2023-44184.

The following software releases have been updated to resolve this specific issue:

Junos OS: 20.4R3-S7, 21.2R3-S5, 21.3R3-S5, 21.4R3-S4, 22.1R3-S2, 22.2R3, 22.3R2-S1, 22.3R3, 22.4R1-S2, 22.4R2, 23.2R1, and all subsequent releases.

Junos OS Evolved 21.4R3-S4-EVO, 22.1R3-S2-EVO, 22.2R3-EVO, 22.3R3-EVO, 22.4R2-EVO, 23.2R1-EVO, and all subsequent releases.

This issue is being tracked as PR 1706285 which is visible on the Customer Support website.

Note: Juniper SIRT's policy [juniper.net] is not to evaluate releases which are beyond End of Engineering (EOE) or End of Life (EOL).

There are no known workarounds for this issue.

The impact of this issue may be temporarily cleared by periodically restarting the management daemon.

To reduce the risk of exploitation enable access control lists (ACLs) and other filtering mechanisms to limit access to the device only from trusted hosts and networks to the NETCONF service.

2023-10-11: Initial Publication
2023-10-13: Removed set system services netconf as minimal required configuration as there are other methods to instantiate netconf commands other than purely through the single set system service location.

• KB16613: Overview of the Juniper Networks SIRT Quarterly Security Bulletin Publication Process [juniper.net]
• KB16765: In which releases are vulnerabilities fixed? [juniper.net]
• KB16446: Common Vulnerability Scoring System (CVSS) and Juniper's Security Advisories [juniper.net]
• Report a Security Vulnerability - How to Contact the Juniper Networks Security Incident Response Team
• CVE-2023-44184 at cve.mitre.org
• https://supportportal.juniper.net/JSA73147 [juniper.net]