CVE-2019-0046 Explained : Impact and Mitigation

A vulnerability in the pfe-chassisd Chassis Manager (CMLC) daemon of Juniper Networks Junos OS allows an attacker to cause a Denial of Service (DoS) to the EX4300 when specific valid broadcast packets create a broadcast storm condition when received on the me0 interface of the EX4300 Series device. This article provides insights into the impact, technical details, and mitigation strategies for CVE-2019-0046.

Understanding CVE-2019-0046

This section delves into the details of the vulnerability and its implications.

What is CVE-2019-0046?

CVE-2019-0046 is a vulnerability in Juniper Networks Junos OS that enables an attacker to trigger a Denial of Service (DoS) on the EX4300 device by generating a broadcast storm condition using specific valid broadcast packets on the me0 interface.

The Impact of CVE-2019-0046

The vulnerability can lead to a sustained Denial of Service (DoS) attack on the affected device, requiring a reboot for service restoration. The impact includes:

Attack Complexity: Low
Attack Vector: Adjacent Network
Availability Impact: High
Base Score: 6.5 (Medium Severity)
No Confidentiality or Integrity Impact
No Privileges Required
User Interaction: None
Scope: Unchanged

Technical Details of CVE-2019-0046

This section provides a deeper dive into the technical aspects of the vulnerability.

Vulnerability Description

The flaw in the pfe-chassisd Chassis Manager (CMLC) daemon allows for the creation of a broadcast storm condition on the EX4300 device, leading to a DoS situation.

Affected Systems and Versions

The following versions of Juniper Networks Junos OS are impacted:

16.1 versions above and including 16.1R1 prior to 16.1R7-S5
17.1 versions prior to 17.1R3
17.2 versions prior to 17.2R3
17.3 versions prior to 17.3R3-S2
17.4 versions prior to 17.4R2
18.1 versions prior to 18.1R3
18.2 versions prior to 18.2R2

Exploitation Mechanism

Juniper SIRT has not detected any malicious exploitation of this vulnerability, indicating a lower immediate risk of active attacks.

Mitigation and Prevention

Learn how to address and prevent the CVE-2019-0046 vulnerability.

Immediate Steps to Take

Apply the provided software releases: 16.1R7-S5, 17.1R3, 17.2R3, 17.3R3-S2, 17.4R2, 18.1R3, 18.2R2, 18.3R1, and subsequent versions.

Long-Term Security Practices

Regularly update Junos OS to the latest patched versions.
Implement network segmentation to limit the impact of potential DoS attacks.

Patching and Updates

Ensure timely installation of software updates and patches to mitigate the vulnerability effectively.