CVE-2019-17558 : Security Advisory and Response

Apache Solr versions 5.0.0 to 8.3.1 are susceptible to Remote Code Execution through the VelocityResponseWriter.

Understanding CVE-2019-17558

This CVE highlights a critical vulnerability in Apache Solr versions 5.0.0 to 8.3.1 that allows for Remote Code Execution through the VelocityResponseWriter.

What is CVE-2019-17558?

The vulnerability enables Remote Code Execution via the VelocityResponseWriter in Apache Solr.
It arises when a Velocity template is provided through Velocity templates in a configset

velocity/

directory or as a parameter.
User-defined configsets may contain renderable templates that could potentially harbor malicious code.
Template rendering via parameters is disabled by default but can be activated by setting

params.resource.loader.enabled

to

true

when defining a response writer.
Starting from Solr 8.4, the params resource loader has been completely removed, and template rendering is only enabled for

trusted

configsets.

The Impact of CVE-2019-17558

Information Disclosure is a significant concern due to the potential for executing arbitrary code.

Technical Details of CVE-2019-17558

Apache Solr's vulnerability to Remote Code Execution through the VelocityResponseWriter has the following technical implications:

Vulnerability Description

Allows Remote Code Execution through the VelocityResponseWriter.
Velocity templates can be exploited via configset

velocity/

directory or as a parameter.

Affected Systems and Versions

Apache Solr versions 5.0.0 to 8.3.1 are vulnerable.

Exploitation Mechanism

Malicious actors can exploit this vulnerability by providing a crafted Velocity template.

Mitigation and Prevention

To address CVE-2019-17558, consider the following mitigation strategies:

Immediate Steps to Take

Disable template rendering via parameters unless necessary.
Regularly monitor for any suspicious activities or unauthorized access.

Long-Term Security Practices

Implement strict access controls and authentication mechanisms.
Regularly update and patch Apache Solr to the latest secure version.

Patching and Updates

Apply the latest patches and updates provided by Apache to mitigate the vulnerability effectively.