CVE-2023-36849

Junos OS and Junos OS Evolved: The l2cpd will crash when a malformed LLDP packet is received

Description

An Improper Check or Handling of Exceptional Conditions vulnerability in the Layer-2 control protocols daemon (l2cpd) of Juniper Networks Junos OS and Junos OS Evolved allows an unauthenticated adjacent attacker to cause a Denial of Service (DoS). When a malformed LLDP packet is received, l2cpd will crash and restart. The impact of the l2cpd crash is reinitialization of STP protocols (RSTP, MSTP or VSTP), and MVRP and ERP. Also, if any services depend on LLDP state (like PoE or VoIP device recognition), then these will also be affected. Continued receipt of such packets will lead to a sustained Denial of Service. This issue affects: Juniper Networks Junos OS 21.4 versions prior to 21.4R3-S3; 22.1 versions prior to 22.1R3-S3; 22.2 versions prior to 22.2R2-S1, 22.2R3; 22.3 versions prior to 22.3R2. Juniper Networks Junos OS Evolved 21.4-EVO versions prior to 21.4R3-S2-EVO; 22.1-EVO versions prior to 22.1R3-S3-EVO; 22.2-EVO versions prior to 22.2R2-S1-EVO, 22.2R3-EVO; 22.3-EVO versions prior to 22.3R2-EVO.

Remediation

Solution:

  • The following software releases have been updated to resolve this specific issue: Junos OS: 21.4R3-S3, 22.1R3-S3, 22.2R2-S1, 22.2R3, 22.3R2, 22.4R1, and all subsequent releases. Junos OS Evolved: 21.4R3-S2-EVO, 22.1R3-S3-EVO, 22.2R2-S1-EVO, 22.2R3-EVO, 22.3R2-EVO, 22.4R1-EVO, and all subsequent releases;

Workaround:

  • There are no available workarounds for this issue. If LLDP and its services are not required, this issue can be mitigated by disabling LLDP.

Category

6.5
CVSS
Severity: Medium
CVSS 3.1 •
EPSS 0.08%
Vendor Advisory juniper.net
Affected: Juniper Networks Junos OS
Affected: Juniper Networks Junos OS Evolved
Published at:
Updated at:

References

Link Tags
https://supportportal.juniper.net/JSA71660 mitigation vendor advisory

Frequently Asked Questions

What is the severity of CVE-2023-36849?
CVE-2023-36849 has been scored as a medium severity vulnerability.
How to fix CVE-2023-36849?
To fix CVE-2023-36849: The following software releases have been updated to resolve this specific issue: Junos OS: 21.4R3-S3, 22.1R3-S3, 22.2R2-S1, 22.2R3, 22.3R2, 22.4R1, and all subsequent releases. Junos OS Evolved: 21.4R3-S2-EVO, 22.1R3-S3-EVO, 22.2R2-S1-EVO, 22.2R3-EVO, 22.3R2-EVO, 22.4R1-EVO, and all subsequent releases;
Is CVE-2023-36849 being actively exploited in the wild?
As for now, there are no information to confirm that CVE-2023-36849 is being actively exploited. According to its EPSS score, there is a ~0% probability that this vulnerability will be exploited by malicious actors in the next 30 days.
What software or system is affected by CVE-2023-36849?
CVE-2023-36849 affects Juniper Networks Junos OS, Juniper Networks Junos OS Evolved.
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