CVE-2019-0051 Explained : Impact and Mitigation

The SSL-Proxy feature on Juniper Networks Junos OS on SRX5000 Series devices is vulnerable to a denial of service attack due to a hardware resource limitation. This CVE entry provides details on the affected versions, impact, and mitigation steps.

Understanding CVE-2019-0051

This CVE involves a vulnerability in the SSL-Proxy feature of Juniper Networks Junos OS on SRX5000 Series devices, potentially leading to a denial of service situation.

What is CVE-2019-0051?

The SSL-Proxy feature on SRX devices is susceptible to a hardware resource limitation, allowing remote SSL/TLS servers to crash the flowd daemon, leading to a denial of service. The issue affects specific versions of Junos OS on SRX5000 Series devices.

The Impact of CVE-2019-0051

CVSS Base Score: 6.5 (Medium Severity)
Attack Vector: Network
Attack Complexity: Low
Privileges Required: None
User Interaction: Required
Availability Impact: High
This vulnerability can result in a prolonged denial of service situation if the flowd daemon repeatedly crashes.

Technical Details of CVE-2019-0051

This section provides detailed technical information about the vulnerability.

Vulnerability Description

The SSL-Proxy feature on SRX devices fails to handle a hardware resource limitation, allowing remote SSL/TLS servers to crash the flowd daemon, potentially leading to a denial of service.

Affected Systems and Versions

The following versions of Juniper Networks Junos OS on SRX5000 Series devices are impacted:

12.3X48 versions prior to 12.3X48-D85
15.1X49 versions prior to 15.1X49-D180
17.3 versions prior to 17.3R3-S7
17.4 versions prior to 17.4R2-S6, 17.4R3
18.1 versions prior to 18.1R3-S8
18.2 versions prior to 18.2R3
18.3 versions prior to 18.3R2
18.4 versions prior to 18.4R2
19.1 versions prior to 19.1R2

Exploitation Mechanism

To exploit this vulnerability, the SSL forward proxy feature must be configured, and clients protected by the SRX device must establish a connection to the malicious server.

Mitigation and Prevention

Learn how to mitigate the impact of CVE-2019-0051.

Immediate Steps to Take

Update to the following software releases: 12.3X48-D85, 15.1X49-D180, 17.3R3-S7, 17.4R2-S6, 17.4R3, 18.1R3-S8, 18.2R3, 18.3R2, 18.4R2, 19.1R2, 19.2R1, or subsequent releases.

Long-Term Security Practices

Regularly monitor and apply security patches provided by Juniper Networks.
Implement network segmentation and access controls to limit exposure to potential threats.

Patching and Updates

Ensure all affected systems are updated with the latest software releases to address the vulnerability.