CVE-2023-36839 : Exploit Details and Defense Strategies
Learn about CVE-2023-36839, an Improper Validation of Specified Quantity in Input vulnerability in Juniper Networks Junos OS and Junos OS Evolved, allowing a DoS attack via specific LLDP packets. Find out about affected systems, impact, and mitigation steps.
A vulnerability has been identified in Juniper Networks Junos OS and Junos OS Evolved that could allow an unauthenticated adjacent attacker to cause a Denial of Service (DoS) by sending specific LLDP packets. This article delves into the details of CVE-2023-36839, its impact, affected systems, exploitation mechanism, and mitigation steps.
Understanding CVE-2023-36839
CVE-2023-36839 is a vulnerability in Juniper Networks Junos OS and Junos OS Evolved that allows an attacker to trigger a Denial of Service (DoS) by sending specific LLDP packets.
What is CVE-2023-36839?
An Improper Validation of Specified Quantity in Input vulnerability in the Layer-2 control protocols daemon (l2cpd) of Juniper Networks Junos OS and Junos OS Evolved allows an unauthenticated adjacent attacker who sends specific LLDP packets to cause a Denial of Service(DoS). This vulnerability is only exploitable on interfaces with LLDP enabled.
The Impact of CVE-2023-36839
The impact of the l2cpd crash is the reinitialization of STP protocols (RSTP, MSTP, or VSTP), MVRP, ERP, and services dependent on LLDP state such as PoE or VoIP device recognition.
Technical Details of CVE-2023-36839
Vulnerability Description
The vulnerability arises due to improper validation of specified input quantity in Layer-2 control protocols.
Affected Systems and Versions
This issue affects various versions of Juniper Networks Junos OS and Junos OS Evolved before specific updates were released.
Exploitation Mechanism
The vulnerability is exploitable on interfaces with LLDP enabled, where an attacker can send specific LLDP packets to trigger a Denial of Service.
Mitigation and Prevention
Immediate Steps to Take
If LLDP and its services are not required, customers can disable LLDP. Disabling telemetry polling also helps mitigate the issue.
Long-Term Security Practices
Ensure that all devices are running the updated software releases provided by Juniper Networks to address this vulnerability.
Patching and Updates
Juniper Networks has released updated software versions for Junos OS and Junos OS Evolved to address the CVE-2023-36839 vulnerability.