CWE
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CWE-611 Individual Dictionary Definition (Draft 9)

Information Leak Through XML External Entity File Disclosure
Weakness ID
Status: Draft

611 (Weakness Variant)

Description

Summary

The product processes an XML document that can contain XML entities with URLs that resolve to documents outside of the intended sphere of control, causing the product to embed incorrect documents into its output.

Extended Description

XML documents optionally contain a Document Type Definition (DTD), which, among other features, enables the definition of "XML entities". It is possible to define an entity locally by providing a substitution string in the form of a URL whose content is substituted for the XML entity when the DTD is processed. The attack can be launched by defining an XML entity whose content is a file URL (which, when processed by the receiving end, is mapped into a file on the server), that is embedded in the XML document, and thus, is fed to the processing application. This application may echo back the data (e.g. in an error message), thereby exposing the file contents.

Observed Examples
ReferenceDescription
CVE-2005-1306 -A browser control can allow remote attackers to determine the existence of files via Javascript containing XML script, aka the "XML External Entity vulnerability."
Context Notes

It's important to note that a URL can have non-HTTP schemes, especially, that a URL such as "file:///c:/winnt/win.ini" designates (in Windows) the file C:\Winnt\win.ini. Similarly, a URL can be used to designate any file on any drive.

Relationships
NatureTypeIDName
ChildOfWeakness ClassWeakness ClassWeakness Class538File and Directory Information Leaks
ChildOfWeakness ClassWeakness ClassWeakness Class673External Influence of Sphere Definition
ChildOfWeakness ClassWeakness ClassWeakness Class610Externally Controlled Reference to a Resource in Another Sphere
Source Taxonomies

Anonymous Tool Vendor (under NDA) -

Page Last Updated: April 22, 2008