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.
This vulnerability is only exploitable on interfaces with LLDP enabled.
[ protocols lldp interface <interface>]
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-2023-36849 .
The following software releases have been updated to resolve this specific issue:
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;
Junos OS: 21.4R3-S3, 22.1R3-S3, 22.2R2-S1, 22.2R3, 22.3R2, 22.4R1, and all subsequent releases.
This issue is being tracked as 1692022
Note: Juniper SIRT's policy is not to evaluate releases which are beyond End of Engineering (EOE) or End of Life (EOL).
There are no available workarounds for this issue.
If LLDP and its services are not required, this issue can be mitigated by disabling LLDP.
2023-07-12: Initial Publication