Re: Fwd: CERT Advisory CA-2000-02

From: Ari Gordon-Schlosberg (regsat_private)
Date: Thu Feb 03 2000 - 12:17:12 PST

  • Next message: fury: "Re: Fwd: CERT Advisory CA-2000-02"

    [Shockroat_private]
    > I'm curious as to how this could be used in a malicious manner, as opposed to
    > just being an annoyance.  I mean, god forbid, people should execute arbitrary
    > javascript on us.  Yes, we've all seen the file upload form exploit and the
    > 1001 ways to crash Internet Explorer through infinite loops, but there's
    > nothing seriously harmful about this, am I right?  Please correct me if I'm
    > wrong.
    >
    
    Yes, you are wrong. :)
    
    Let me explain: the javascript issue is not a huge one, although there are
    some issues. I don't know enough about javascript to get into it.
    
    I think the best example of where this could be a problem would on a site
    like amazon.com.  If I can inject HTML into my customer review, I can start
    reaping passwords or credit card numbers.  By studying the format of the
    amazon HTML, I can make it look like I inserted some sort of prize form
    into the web page: I ask for their username and password and they press
    submit... that then posts to a cgi on my server.  Boom!  I have their
    account.  Or I embed an applet, the net result being the same.  This is a
    real issue.
    
    Basically, it boils down the fact that most users will assume that any
    HTML/Applet/form/script that shows up on a foo.com webpage was authored by
    someone at foo.com, and any information that they send via their web
    browser will be going to and only to foo.com.  Injection of an attacker's
    HTML into a a foo.com webpage can exploit this assumption to steal
    sensitive information.
    
    --
    Ari							there is no spoon
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