IE 5.0 security vulnerabilities - %01 bug again

From: Georgi Guninski (joroat_private)
Date: Thu Apr 08 1999 - 21:15:12 PDT

  • Next message: Eric Stevens: "Re: IE 5.0 security vulnerabilities - %01 bug again"

    There is a security bug in Internet Explorer 5.0 which circumvents
    "Cross-frame security" and
    opens several security holes.
    
    This is a modification of the "%01 security bug" (that was fixed in IE
    5.0) I found in January.
    
    The problem seems to be in the "Microsoft Scriptlet Component".
    If you add '%01someURL' after the URL you pass to "Microsoft Scriptlet
    Component", IE thinks that the document is
    loaded from the domain of 'someURL'.
    
    Some of the vulnerabilities are:
    
    1) IE allows reading local files and sending them to an arbitrary
    server.
    The filename must be known.
    
    The bug may be exploited using HTML mail message.
    
    Demo is available at: http://www.nat.bg/~joro/scriptlet.html
    
    2) IE allows "window spoofing".
    After visiting a hostile page (or clicking a hostile link) a window is
    opened and its
    location is a trusted site. However, the content of the window is not
    that of the original site,
    but it is supplied by the owner of the page. So, the user is misled he
    is browising
    a trusted site, while he is browsing a hostile page and may provide
    sensitive information,
    such as credit card number.
    
    The bug may be exploited using HTML mail message.
    
    Demo is available at: http://www.nat.bg/~joro/scrspoof.html
    
    
    Workaround: Disable Javascript
    
    Regards,
    Georgi Guninski
    



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