Description
This vulnerability in Apache Solr 6.0.0 to 6.6.3, 7.0.0 to 7.3.0 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. 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.
Remediation
References
https://mail-archives.apache.org/mod_mbox/www-announce/201805.mbox/%3C08a801d3f0f9%24df46d300%249dd47900%24%40apache.org%3E
http://www.securityfocus.com/bid/104239
https://lists.apache.org/thread.html/r204ba2a9ea750f38d789d2bb429cc0925ad6133deea7cbc3001d96b5%40%3Csolr-user.lucene.apache.org%3E
Related Vulnerabilities
CVE-2022-43423 Vulnerability in maven package com.compuware.jenkins:compuware-scm-downloader
CVE-2020-16037 Vulnerability in maven package org.webjars.npm:electron
CVE-2023-40178 Vulnerability in npm package @node-saml/node-saml
CVE-2021-31805 Vulnerability in maven package org.apache.struts:struts2-core
CVE-2023-37960 Vulnerability in maven package io.jenkins.plugins:mathworks-polyspace