[91641] in North American Network Operators' Group
Re: ISP wants to stop outgoing web based spam
daemon@ATHENA.MIT.EDU (David Andersen)
Wed Aug 9 14:26:42 2006
In-Reply-To: <17626.9804.297395.580561@world.std.com>
Cc: Jeroen Massar <jeroen@unfix.org>,
"Mills, Charles" <cmills@accessdc.com>, Nanog <nanog@merit.edu>
From: David Andersen <dga+@cs.cmu.edu>
Date: Wed, 9 Aug 2006 14:24:47 -0400
To: Barry Shein <bzs@world.std.com>
Errors-To: owner-nanog@merit.edu
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On Aug 9, 2006, at 2:15 PM, Barry Shein wrote:
>
>
> I think what was being talked about was that a lot of spam now comes
> as embedded images which unpack into ads for the usual stuff. It's
> actually been going on for a few years but I guess as the other stuff
> gets more and more effectively blocked this form becomes more salient.
>
> Thus far I don't know of any good filter for these.
>
> Common spam software seems to rotate or vary these slightly so it's
> not as simple as comparing to one you've seen before. Since the image
> formats are compressed, usually gif, tiny changes can ripple through
> the entire encoding.
Now we'll have to throw our inbound email through an OCR.
Then the spammers will start rotating the text or changing the
background.
So we'll write a better OCR that can see through such transformations.
At which point, the spammers will be happy, because we'll have given
them a tool to break Captchas.
Hmmm...
(Or just reject mail with images in it. :)
-Dave
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