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SYNTHESIS OF THE VULNERABILITY

An attacker can transmit malicious XML data to Perl XML::LibXML,
in order to read a file, scan sites, or trigger a denial of
service.

Impacted products: Debian, Fedora, MBS, Perl Module, Ubuntu

Severity: 2/4

Creation date: 27/04/2015

DESCRIPTION OF THE VULNERABILITY

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 must be disabled to process XML data coming from an
untrusted source.

However, the Perl XML::LibXML parser allows external entities when
it is loaded with:
$parser = XML::LibXML->new
$XML_DOC = $parser->load_xml

An attacker can therefore transmit malicious XML data to Perl
XML::LibXML, in order to read a file, scan sites, or trigger a
denial of service.

ACCESS TO THE COMPLETE VIGIL@NCE BULLETIN

http://vigilance.fr/vulnerability/Perl-XML-LibXML-external-XML-entity-injection-16719