XML External Entity (XXE) Injection Affecting org.apache.santuario:xmlsec package, versions [2.0.3, 2.1.4)
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
Do your applications use this vulnerable package?
In a few clicks we can analyze your entire application and see what components are vulnerable in your application, and suggest you quick fixes.
Test your applicationsSnyk Learn
Learn about XML External Entity (XXE) Injection vulnerabilities in an interactive lesson.
Start learning- Snyk IDSNYK-JAVA-ORGAPACHESANTUARIO-460281
- published25 Aug 2019
- disclosed10 May 2019
- creditSean Mullan
Introduced: 10 May 2019
CVE-2019-12400 (opens in a new tab)How to fix?
Upgrade org.apache.santuario:xmlsec to version 2.1.4 or higher.
Overview
org.apache.santuario:xmlsec is a package to provide implementation of the primary security standards for XML, XML-Signature Syntax and Processing and XML Encryption Syntax and Processing.
Affected versions of this package are vulnerable to XML External Entity (XXE) Injection. In version 2.0.3 a caching mechanism was introduced to speed up creating new XML documents using a static pool of DocumentBuilders. However, if some untrusted code can register a malicious implementation with the thread context class loader first, then this implementation might be cached and re-used by Apache Santuario - XML Security for Java, leading to potential security flaws when validating signed documents, etc.
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.