Re: The Dangers of Allowing Users to Post Images

From: Dan Harkless (dan-bugtraqat_private)
Date: Tue Jul 31 2001 - 09:40:43 PDT

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    Michal Szokolo <msz@kill-spammers.pmp.com.pl> writes:
    > John Percival wrote:
    > > I'm going to try and throw another issue into this discussion now too:
    > > denial of service. We have discussed it for attacking remote servers, but
    > > not for the client viewing the image. It's something else that I spotted
    > > while I was playing around with this issue just now.
    > > 
    > > If you have images that include a mailto:meat_private source,
    > > then the default handler for mailto: links is opened up. Be that Outlook,
    > > Netscape Composer, Eudora, or whatever else you care to use.
    > > 
    > > So if someone embedded 100 (arbitrary figure) mailto: images in a page,
    > > then this would do a lot of harm to the user's computer. At best, it
    > > would get very busy for a few minutes creating new emails, and would be
    > > a pain to clear up. At worst, it could bring the whole system crashing
    > > down.
    > 
    > Netscape 4.77 crashes at about 50 such IMG tags, IF they are different
    > (simply putting mailto:fakeluser@fakedomain 100 times won't work (opens
    > only 2 message windows)), but if you go with some script... instant
    > crash (try it now free of charge at http://msz.pmp.com.pl/boom/ ;-)).
    
    Sorry for the very late reply to this thread, but in case anybody's
    wondering whether the recently-released 4.78 fixes this bug, it does not.
    
    When I visit the page, though (and perhaps on version 4.78 in general), it
    doesn't crash until you click on the close box for one of the Composer
    windows. 
    
    I tested on Win2K Pro.
    
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