[CVE-2019-0193] Apache Solr, Remote Code Execution via DataImportHandler

[David Smiley <ds...@apache.org>]

The DataImportHandler, an optional but popular module to pull in data from
databases and other sources, has a feature in which the whole DIH
configuration can come from a request's "dataConfig" parameter. The debug
mode of the DIH admin screen uses this to allow convenient debugging /
development of a DIH config. Since a DIH config can contain scripts, this
parameter is a security risk. Starting with version 8.2.0 of Solr, use of
this parameter requires setting the Java System property
"enable.dih.dataConfigParam" to true.

Mitigations:
* Upgrade to 8.2.0 or later, which is secure by default.
* or, edit solrconfig.xml to configure all DataImportHandler usages with an
"invariants" section listing the "dataConfig" parameter set to am empty
string.
* Ensure your network settings are configured so that only trusted traffic
communicates with Solr, especially to the DIH request handler.  This is a
best practice to all of Solr.

Credits:
* Michael Stepankin (JPMorgan Chase)

References:
* https://issues.apache.org/jira/browse/SOLR-13669
* https://cwiki.apache.org/confluence/display/solr/SolrSecurity

Please direct any replies as either comments in the JIRA issue above or to
solr-user@lucene.apache.org