XML External Entity (XXE) Injection Affecting org.apache.solr:solr-dataimporthandler package, versions [,8.0.0)
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Test your applications- Snyk ID SNYK-JAVA-ORGAPACHESOLR-535577
- published 10 Oct 2019
- disclosed 31 Jul 2019
- credit Unknown
Introduced: 31 Jul 2019
CVE-2019-0193 Open this link in a new tabHow to fix?
Upgrade org.apache.solr:solr-dataimporthandler to version 8.0.0 or higher.
Overview
org.apache.solr:solr-dataimporthandler is a Solr DataImportHandler Java Library.
Affected versions of this package are vulnerable to XML External Entity (XXE) Injection. It is possible for an attacker to inject external entities through DataImportHandler's dataConfig parameter which is used for setting the whole DIH configuration when using debug mode of the DIH admin screen.
Details
XXE Injection is a type of attack against an application that parses XML input. XML is a markup language that defines a set of rules for encoding documents in a format that is both human-readable and machine-readable. By default, many XML processors allow specification of an external entity, a URI that is dereferenced and evaluated during XML processing. When an XML document is being parsed, the parser can make a request and include the content at the specified URI inside of the XML document.
Attacks can include disclosing local files, which may contain sensitive data such as passwords or private user data, using file: schemes or relative paths in the system identifier.
For example, below is a sample XML document, containing an XML element- username.
<xml>
<?xml version="1.0" encoding="ISO-8859-1"?>
<username>John</username>
</xml>
An external XML entity - xxe, is defined using a system identifier and present within a DOCTYPE header. These entities can access local or remote content. For example the below code contains an external XML entity that would fetch the content of /etc/passwd and display it to the user rendered by username.
<xml>
<?xml version="1.0" encoding="ISO-8859-1"?>
<!DOCTYPE foo [
<!ENTITY xxe SYSTEM "file:///etc/passwd" >]>
<username>&xxe;</username>
</xml>
Other XXE Injection attacks can access local resources that may not stop returning data, possibly impacting application availability and leading to Denial of Service.