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Message-ID: <20051006224701.GS6095@clanspum.net>
Date: Thu Oct 6 23:47:09 2005
From: houdini+full-disclosure at clanspum.net (Bill Weiss)
Subject: Interesting idea for a covert channel or I just
didn't research enough?
Frank Knobbe(frank@...bbe.us)@Thu, Oct 06, 2005 at 04:53:19PM -0500:
> On Thu, 2005-10-06 at 16:52 -0400, Michael Holstein wrote:
> > Webbugs, which use unique URLs under an <IMG> tag, are an excellent
> > example of using logfiles to <DO STUFF>.
>
> Except that "vi", "less" or "notepad" don't import anything.
>
> You're not looking at your log files with a web browser, do you??
He was referring not to the log viewer executing something, but
transmission of data to the server containing the URL (stored in their
logs).
A common spammer trick, used also in more legit ways, is to send an email
with an image in it. The image is actually a CGI script that takes a
parameter, logs it, then kicks out an image. "Webbugs" tend to be 1px
square, and possibly transparent. Using this can automate testing if
email addresses are valid (by sending each address a different unique
tracking URL).
--
Bill Weiss
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