CVE-2023-36849: Junos OS and Junos OS Evolved: The l2cpd will crash when a malformed LLDP packet is received
First published: Fri Jul 14 2023(Updated: )
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.
Credit: sirt@juniper.net sirt@juniper.net
| Affected Software | Affected Version | How to fix |
|---|---|---|
| Juniper JUNOS | =21.4 | |
| Juniper JUNOS | =21.4-r1 | |
| Juniper JUNOS | =21.4-r1-s1 | |
| Juniper JUNOS | =21.4-r1-s2 | |
| Juniper JUNOS | =21.4-r2 | |
| Juniper JUNOS | =21.4-r2-s1 | |
| Juniper JUNOS | =21.4-r2-s2 | |
| Juniper JUNOS | =21.4-r3 | |
| Juniper JUNOS | =21.4-r3-s1 | |
| Juniper JUNOS | =21.4-r3-s2 | |
| Juniper JUNOS | =22.1-r1 | |
| Juniper JUNOS | =22.1-r1-s1 | |
| Juniper JUNOS | =22.1-r1-s2 | |
| Juniper JUNOS | =22.1-r2 | |
| Juniper JUNOS | =22.1-r2-s1 | |
| Juniper JUNOS | =22.1-r2-s2 | |
| Juniper JUNOS | =22.1-r3 | |
| Juniper JUNOS | =22.1-r3-s1 | |
| Juniper JUNOS | =22.1-r3-s2 | |
| Juniper JUNOS | =22.2-r1 | |
| Juniper JUNOS | =22.2-r1-s1 | |
| Juniper JUNOS | =22.2-r1-s2 | |
| Juniper JUNOS | =22.2-r2 | |
| Juniper JUNOS | =22.3-r1 | |
| Juniper JUNOS | =22.3-r1-s1 | |
| Juniper JUNOS | =22.3-r1-s2 | |
| Juniper Junos Os Evolved | =21.4 | |
| Juniper Junos Os Evolved | =21.4-r1 | |
| Juniper Junos Os Evolved | =21.4-r1-s1 | |
| Juniper Junos Os Evolved | =21.4-r1-s2 | |
| Juniper Junos Os Evolved | =21.4-r2 | |
| Juniper Junos Os Evolved | =21.4-r2-s1 | |
| Juniper Junos Os Evolved | =21.4-r2-s2 | |
| Juniper Junos Os Evolved | =21.4-r3 | |
| Juniper Junos Os Evolved | =21.4-r3-s1 | |
| Juniper Junos Os Evolved | =22.1-r1 | |
| Juniper Junos Os Evolved | =22.1-r1-s1 | |
| Juniper Junos Os Evolved | =22.1-r1-s2 | |
| Juniper Junos Os Evolved | =22.1-r2 | |
| Juniper Junos Os Evolved | =22.1-r2-s1 | |
| Juniper Junos Os Evolved | =22.1-r3 | |
| Juniper Junos Os Evolved | =22.1-r3-s1 | |
| Juniper Junos Os Evolved | =22.1-r3-s2 | |
| Juniper Junos Os Evolved | =22.2-r1 | |
| Juniper Junos Os Evolved | =22.2-r1-s1 | |
| Juniper Junos Os Evolved | =22.2-r2 | |
| Juniper Junos Os Evolved | =22.3-r1 | |
| Juniper Junos Os Evolved | =22.3-r1-s1 | |
| Juniper Junos Os Evolved | =22.3-r1-s2 |
Remedy
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;
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Reference Links
Frequently Asked Questions
What is CVE-2023-36849?
CVE-2023-36849 is 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.
How does CVE-2023-36849 impact Juniper Networks Junos OS?
CVE-2023-36849 can allow an unauthenticated adjacent attacker to cause a Denial of Service (DoS).
Is authentication required to exploit CVE-2023-36849?
No, CVE-2023-36849 can be exploited by an unauthenticated adjacent attacker.
What is the severity of CVE-2023-36849?
CVE-2023-36849 has a severity level of medium, with a CVSS score of 6.5.
How can I fix CVE-2023-36849?
Apply the necessary updates or patches provided by Juniper Networks. Please refer to the Juniper Networks support portal for more information: https://supportportal.juniper.net/JSA71660
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