Title: CVE-2019-17558: Apache Solr RCE through VelocityResponseWriter category: solr/security cve: CVE-2019-17558

Severity: High

Vendor:
The Apache Software Foundation

Versions Affected: 5.0.0 to 8.3.1

Description:
The affected versions are vulnerable to a Remote Code Execution through the VelocityResponseWriter. A Velocity template can be provided through Velocity templates in a configset velocity/ directory or as a parameter. A user defined configset could contain renderable, potentially malicious, templates. Parameter provided templates are disabled by default, but can be enabled by setting params.resource.loader.enabled by defining a response writer with that setting set to true. Defining a response writer requires configuration API access.

Solr 8.4 removed the params resource loader entirely, and only enables the configset-provided template rendering when the configset is trusted (has been uploaded by an authenticated user).

Mitigation:
Ensure your network settings are configured so that only trusted traffic communicates with Solr, especially to the configuration APIs.

Credit:
Github user s00py

References:

• https://issues.apache.org/jira/browse/SOLR-13971
• https://issues.apache.org/jira/browse/SOLR-14025
• https://cwiki.apache.org/confluence/display/SOLR/SolrSecurity