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Product Affected

This issue affects all versions of Junos OS. Affected platforms: MX Series.

Severity

Medium

Severity Assessment (CVSS) Score

5.5 (CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H)

Problem

An Improper Release of Memory Before Removing Last Reference vulnerability in Packet Forwarding Engine (PFE) of Juniper Networks Junos OS allows a local, low privileged attacker to cause an FPC crash, leading to Denial of Service (DoS).

On all Junos MX Series with MPC1 - MPC9, LC480, LC2101, MX10003, and MX80, when Connectivity-Fault-Management (CFM) is enabled in a VPLS scenario, and a specific LDP related command is run, an FPC will crash and reboot. Continued execution of this specific LDP command can lead to sustained Denial of Service condition.

This issue affects:

Juniper Networks Junos OS on MX Series

All versions prior to 20.4R3-S7;
21.1 versions prior to 21.1R3-S5;
21.2 versions prior to 21.2R3-S4;
21.3 versions prior to 21.3R3-S4;
21.4 versions prior to 21.4R3-S3;
22.1 versions prior to 22.1R3-S1;
22.2 versions prior to 22.2R2-S1, 22.2R3;
22.3 versions prior to 22.3R1-S2, 22.3R2.

For this issue to occur, following minimal configuration is required.

[ ldp interface <interface1> ]
[ interfaces <interface1> flexible-vlan-tagging ]
[ interfaces <interface1> encapsulation vlan-vpls ]
[ protocols oam ethernet connectivity-fault-management maintenance-domain <md-name> interface <interface2> ]
[ routing-instances <md-name> instance-type vpls ]
[ routing-instances <md-name> interface <interface1> ]

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-2023-44193.

Solution

The following software releases have been updated to resolve this specific issue: 20.4R3-S7, 21.1R3-S5, 21.2R3-S4, 21.3R3-S4, 21.4R3-S3, 22.1R3-S1, 22.2R2-S1, 22.2R3, 22.3R1-S2, 22.3R2, 22.4R1, and all subsequent releases.

This issue is being tracked as PR 1668419 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).

Workaround

This issue can be avoided by disabling CFM MIP functionality.

[ protocols oam ethernet connectivity-fault-management maintenance-domain <md-name> mip-half-function none ]

Severity Assessment

Information for how Juniper Networks uses CVSS can be found at KB 16446 [juniper.net] "Common Vulnerability Scoring System (CVSS) and Juniper's Security Advisories."

Modification History