CVE-2018-8010: XXE vulnerability due to Apache Solr configset upload Severity: High
Vendor: The Apache Software Foundation Versions Affected: Solr 6.0.0 to 6.6.3 Solr 7.0.0 to 7.3.0 Description: The details of this vulnerability were reported internally by one of Apache Solr's committers. This vulnerability relates to an XML external entity expansion (XXE) in Solr config files (solrconfig.xml, schema.xml, managed-schema). In addition, Xinclude functionality provided in these config files is also affected in a similar way. The vulnerability can be used as XXE using file/ftp/http protocols in order to read arbitrary local files from the Solr server or the internal network. See [1] for more details. Mitigation: Users are advised to upgrade to either Solr 6.6.4 or Solr 7.3.1 releases both of which address the vulnerability. Once upgrade is complete, no other steps are required. Those releases only allow external entities and Xincludes that refer to local files / zookeeper resources below the Solr instance directory (using Solr's ResourceLoader); usage of absolute URLs is denied. Keep in mind, that external entities and XInclude are explicitly supported to better structure config files in large installations. Before Solr 6 this was no problem, as config files were not accessible through the APIs. If users are unable to upgrade to Solr 6.6.4 or Solr 7.3.1 then they are advised to make sure that Solr instances are only used locally without access to public internet, so the vulnerability cannot be exploited. In addition, reverse proxies should be guarded to not allow end users to reach the configset APIs. Please refer to [2] on how to correctly secure Solr servers. Solr 5.x and earlier are not affected by this vulnerability; those versions do not allow to upload configsets via the API. Nevertheless, users should upgrade those versions as soon as possible, because there may be other ways to inject config files through file upload functionality of the old web interface. Those versions are no longer maintained, so no deep analysis was done. Credit: Ananthesh, Ishan Chattopadhyaya References: [1] https://issues.apache.org/jira/browse/SOLR-12316 [2] https://wiki.apache.org/solr/SolrSecurity ----- Uwe Schindler uschind...@apache.org ASF Member, Apache Lucene PMC / Committer Bremen, Germany http://lucene.apache.org/