To webmail developpers : there is something interesting for you hidden in this post. The Hotmail problem was a "evil html filtering" problem in incoming e-mails. It was possible to bypass the filter by injecting javascript with XML, when parsed with IE. See : http://spoor12.edup.tudelft.nl/SkyLined/docs/ie.hotmail.howto.css.html *** I guess that many other webmails are vulnerable to this attack. *** I verified that Yahoo is vulnerable with IE 5.5 (but they have other bugs and they don't care, see http://online.securityfocus.com/archive/1/265464). I did not checked other webmails, but I am sure almost every one can be cracked this way. > The fix: as far as I could find out they now replace > the properties 'dataFld', 'dataFormatAs' > and 'dataSrc' of any HTML tag > with 'xdataFld', 'xdataFormatAs' and 'xdataSrc' to > prevent XML generation of HTML alltogether. The implication of executing javascript is that an incoming email can control the mailbox of the user. It is also possible to send the session cookie to a cgi script and read remotely all the e-mails. (BTW, it is still possible to do that on Hotmail and on almost every webmail, since they don't check the IP address, even without this XML trick cause their filters are sooo bad) I fear that a cross-platform and cross-site webmail worm deleting all the emails and spreading could appear in the near future. Please Hotmail Yahoo & co, do something before it comes true... FozZy Hackademy / Hackerz Voice http://www.dmpfrance.com/inted.html
This archive was generated by hypermail 2b30 : Sat Apr 20 2002 - 21:03:11 PDT