Vigil@nce - Raptor: file reading via RDF with an XML external entity
April 2012 by Vigil@nce
This bulletin was written by Vigil@nce : http://vigilance.fr/offer
SYNTHESIS OF THE VULNERABILITY
An attacker can invite the victim to open a malicious RDF file with an application linked to Raptor, in order to obtain a copy of victim’s files.
Creation date: 23/03/2012
Red Hat Enterprise Linux
SUSE Linux Enterprise Desktop
SUSE Linux Enterprise Server
Unix - plateform
DESCRIPTION OF THE VULNERABILITY
The RDF (Resource Description Framework) format is used to represent data. It is based on XML.
XML data can contain external entities (DTD):
A program which reads these XML data can replace these entities by data coming from the indicated file. When the program uses XML data coming from an untrusted source, this behavior leads to:
- content disclosure from files of the server
- private web site scan
- a denial of service by opening a blocking file
This feature thus must be disabled to process data coming from an untrusted source.
The Raptor library implements RDF. However, Raptor does not disable this feature for RDF files.
An attacker can therefore invite the victim to open a malicious RDF file with an application linked to Raptor, in order to obtain a copy of victim’s files.
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