CVE-2020-1685 : What You Need to Know

This CVE-2020-1685 article provides an overview of the vulnerability affecting Juniper Networks Junos OS on EX4600 and QFX5K Series devices.

Understanding CVE-2020-1685

This CVE involves a specific issue related to stateless firewall filters in Juniper Networks devices utilizing VXLAN technology.

What is CVE-2020-1685?

The vulnerability occurs when the discard action in firewall filters fails to discard traffic properly under specific conditions, potentially causing unintended traffic to pass through.

The Impact of CVE-2020-1685

The incomplete discard action in stateless firewall filters can lead to unexpected traffic passing through the interface, compromising network security.

Technical Details of CVE-2020-1685

This section outlines technical information related to the CVE.

Vulnerability Description

Stateful firewall filters configured with 'user-vlan-id' match conditions may fail to discard traffic not matching the specified VLAN ID, allowing unintended traffic to pass.

Affected Systems and Versions

Affected Systems: Juniper Networks EX4600 and QFX5K Series
Affected Versions: 18.1, 18.2, 18.3, 18.4, 19.1, 19.2

Exploitation Mechanism

Exploitation is through misconfigured firewall filters using the 'user-vlan-id' match criterion.

Mitigation and Prevention

Protect your systems by following the mitigation guidelines below:

Immediate Steps to Take

Avoid using the 'user-vlan-id' match criteria in firewall filter configurations.

Long-Term Security Practices

Regularly review and update firewall configurations to ensure proper traffic filtering.

Patching and Updates

Update to the latest Junos OS software versions: 18.1R3-S7, 18.2R2-S7, 18.2R3-S1, 18.3R1-S5, 18.3R2-S4, 18.3R3, 18.4R1-S7, 18.4R2-S1, 18.4R3, 19.1R1-S5, 19.1R2, 19.2R1-S5, 19.2R2, 19.3R1, or subsequent releases.