CVE-2019-0039 : Exploit Details and Defense Strategies

Enabling the REST API in Junos OS can expose login credentials to brute force attacks. Learn about the impact, affected systems, and mitigation steps.

Understanding CVE-2019-0039

What is CVE-2019-0039?

Enabling the REST API in Junos OS can make login credentials vulnerable to brute force attacks due to a high default connection limit.

The Impact of CVE-2019-0039

Enabling the REST API in Junos OS can lead to potential brute force attacks on login credentials, compromising system security.

Technical Details of CVE-2019-0039

Vulnerability Description

The vulnerability arises from the high default connection limit of the REST API, allowing attackers to exploit weak password policies.

Affected Systems and Versions

Junos OS versions 14.1X53-D49, 15.1F6-S12, 15.1R7-S3, 15.1X49-D160, 15.1X53-D236, 15.1X53-D495, 15.1X53-D591, 15.1X53-D69, 16.1R3-S10, 16.1R4-S12, 16.1R6-S6, 16.1R7-S3, 16.1X65-D49, 16.2R2-S7, 17.1R2-S10, 17.1R3, 17.2R1-S8, 17.2R3-S1, 17.3R3-S2, 17.4R1-S6, 17.4R2-S2, 18.1R2-S4, 18.1R3-S1, 18.2R1-S5, 18.2X75-D30, 18.3R1-S1.

Exploitation Mechanism

Attackers can exploit the vulnerability by using advanced scripting techniques to guess passwords due to the high default connection limit of the REST API.

Mitigation and Prevention

Immediate Steps to Take

Update to the patched versions of Junos OS to mitigate the vulnerability.
Set a connection limit on the REST API to restrict unauthorized access.
Use access lists or firewall filters to limit API access to trusted hosts only.

Long-Term Security Practices

Enforce a strong password policy to prevent successful brute force attacks.

Patching and Updates

Ensure all affected systems are updated to the patched versions of Junos OS.