CVE-2018-0026 Explained : Impact and Mitigation

After Junos OS device reboot or upgrade, the stateless firewall filter configuration may not take effect. This issue affects Juniper Networks Junos OS versions 15.1R4, 15.1R5, 15.1R6, and 15.1X8 prior to 15.1X8.3.

Understanding CVE-2018-0026

This CVE involves stateless IP firewall filter rules failing to work as expected after a reboot or upgrade on Junos OS devices.

What is CVE-2018-0026?

The configuration of stateless firewall filters may fail to take effect after a reboot or upgrade of a Junos OS device. This issue impacts firewall filters for all address families.

The Impact of CVE-2018-0026

Attack Complexity: Low
Attack Vector: Network
Base Score: 4.7 (Medium)
Integrity Impact: Low
User Interaction: Required
Scope: Changed
No known malicious exploitation reported
Affected versions: Junos OS 15.1R4, 15.1R5, 15.1R6, and 15.1X8 prior to 15.1X8.3
Impact types: Firewall Bypass, Denial of Service

Technical Details of CVE-2018-0026

This section provides detailed technical information about the vulnerability.

Vulnerability Description

The issue causes stateless firewall filters to stop working correctly after a device reboot or upgrade, affecting all address families.

Affected Systems and Versions

Affected Versions: Junos OS 15.1R4, 15.1R5, 15.1R6, and 15.1X8 (prior to 15.1X8.3)
Vendor: Juniper Networks

Exploitation Mechanism

The vulnerability requires network access and user interaction to exploit. No malicious exploitation has been reported.

Mitigation and Prevention

Protect your systems from CVE-2018-0026 with the following steps:

Immediate Steps to Take

Upgrade to fixed software releases: 15.1R7, 15.1X8.3, or later
Monitor for any unauthorized changes in firewall filter configurations

Long-Term Security Practices

Regularly review and update firewall filter configurations
Implement network segmentation to limit the impact of potential breaches

Patching and Updates

Apply the provided software updates to address the vulnerability