XML External Entity (XXE) Injection Affecting batik:batik-dom Open this link in a new tab package, versions [0,]


0.0
high
  • Attack Complexity

    Low

  • User Interaction

    Required

  • Confidentiality

    High

  • Availability

    High

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  • snyk-id

    SNYK-JAVA-BATIK-31390

  • published

    21 May 2017

  • disclosed

    18 Apr 2017

  • credit

    Unknown

How to fix?

There is no fixed version for batik:batik-dom.

Overview

batik:batik-dom is a package that provides an implementation of the DOM level 2 core module.

Affected versions of this package are vulnerable to XML External Entity (XXE) Injection. Files lying on the filesystem of the server which uses batik can be revealed to arbitrary users who send maliciously formed SVG files. The file types that can be shown depend on the user context in which the exploitable application is running. If the user is root a full compromise of the server - including confidential or sensitive files - would be possible. XXE can also be used to attack the availability of the server via denial of service as the references within a xml document can trivially trigger an amplification attack.

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.