Re: The Dangers of Allowing Users to Post Images

["Dan Harkless" <dan-bugtraq () dilvish speed net>]

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:me () my host somewhere com 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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