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Product Affected

This issue affects all versions of Junos OS and Junos OS Evolved.

Severity

Medium

Severity Assessment (CVSS) Score

CVSS 3.1: 6.5 (CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H)

CVSS 4.0: 7.1 (CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:L)

Problem

An Improper Handling of Exceptional Conditions vulnerability in Juniper Networks Junos OS and Junos OS Evolved allows an adjacent unauthenticated attacker to cause a Denial of Service (DoS), which causes the l2cpd process to crash by sending a specific TLV.

The l2cpd process is responsible for layer 2 control protocols, such as STP, RSTP, MSTP, VSTP, ERP, and LLDP. The impact of the l2cpd crash is reinitialization of STP protocols (RSTP, MSTP or VSTP), and MVRP and ERP, leading to a Denial of Service. Continued receipt and processing of this specific TLV will create a sustained Denial of Service (DoS) condition.

This issue affects:

Junos OS:

all versions before 20.4R3-S9,
from 21.2 before 21.2R3-S7,
from 21.3 before 21.3R3-S5,
from 21.4 before 21.4R3-S4,
from 22.1 before 22.1R3-S4,
from 22.2 before 22.2R3-S2,
from 22.3 before 22.3R2-S2, 22.3R3-S1,
from 22.4 before 22.4R2-S2, 22.4R3,
from 23.2 before 23.2R1-S1, 23.2R2;

Junos OS Evolved:

all versions before 21.2R3-S7,
from 21.3 before 21.3R3-S5-EVO,
from 21.4 before 21.4R3-S5-EVO,
from 22.1 before 22.1R3-S4-EVO,
from 22.2 before 22.2R3-S2-EVO,
from 22.3 before 22.3R2-S2-EVO, 22.3R3-S1-EVO,
from 22.4 before 22.4R2-S2-EVO, 22.4R3-EVO,
from 23.2 before 23.2R1-S1-EVO, 23.2R2-EVO.

A sample configuration enabling LLDP is shown below:

[set protocols lldp interface all]
[set interfaces ge-0/0/0 lldp ...]

Solution

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

Junos OS: 20.4R3-S9, 21.2R3-S7, 21.3R3-S5, 21.4R3-S4, 22.1R3-S4, 22.2R3-S2, 22.3R2-S2, 22.3R3-S1, 22.4R2-S2, 22.4R3, 23.2R1-S1, 23.2R2, 23.4R1, and all subsequent releases.
Junos OS Evolved: 21.2R3-S7-EVO, 21.3R3-S5-EVO, 21.4R3-S5-EVO, 22.1R3-S4-EVO, 22.2R3-S2-EVO, 22.3R2-S2-EVO, 22.3R3-S1-EVO, 22.4R2-S2-EVO, 22.4R3-EVO, 23.2R1-S1-EVO, 23.2R2-EVO, 23.4R1-EVO, and all subsequent releases.

This issue is being tracked as 1748720 which is visible on the Customer Support website.

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

Workaround

There are no known workarounds for this issue.

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