Why doesn't DCC help against image spam?

Dennis Willson taz at taz-mania.com
Wed Dec 27 18:52:26 CET 2006


The only "image" Spam that is currently getting through my filters is 
the "stock scam" images and they are different everytime I see it and 
they are using wavy text, odd colors and mixed fonts, etc... to try 
and fool the OCR scanners.

So, my question would be, how effective are the OCR scanners when the 
Spammers are doing this?

Since I put my new Spam Trap in place I have seen a reduction of this 
Spam getting through. It appears the honeypots are seeing the sources 
of the images first (or close to it) and stopping that source... 
ofcourse they rotate sources through out the day, but the honeypots 
are getting over 2000-3000 new IP address every day. The "hit rate" on 
the now blacklisted source is fairly high.



On Wed, 27 Dec 2006 11:21:47 -0500
  Matt Kettler <mkettler at evi-inc.com> wrote:
>Pete Russell wrote:
>> 
>> 
>> Glenn Steen wrote:
>>>>
>>>> FuzzyOCR runs by default with a low priority (runs as last SA test), 
>>>>so
>>>> it only run when the SA score (so far) is > $X, so set that to your 
>>>>low
>>>> threshold, and FuzzyOCR only runs on spam that hasn't been tagged 
>>>>yet.
>>>> Works quite well, and doesn't take all that much cpu, since > 70% of 
>>>>the
>>>> image spam is caught by the other methods.
>>> True enough... When I've been testing I haven't been taking that 
>>>into
>>> consideration (looking at "synthetic" situations can blind one to
>>> things:-). Will likely implement it in production some time early 
>>>next
>>> year then. Thanks Ken.
>> 
>> Should one use imageinfo OR FuzzyOCR, or both together?
>
>If you have plenty of CPU cycles to spare, go for both.
>
>imageinfo is pretty lightweight, so anyone should be able to use it 
>unless their
>SA box is already overloaded.
>
>FuzzyOCR isn't too bad because of the priority thing, but it is still 
>a
>noticeable load. Folks with servers that are already getting to be a 
>little bit
>marginal should skip this.
>
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--------------------------------------------------
Dennis Willson

taz at taz-mania.com
http://www.taz-mania.com

Ham (Extra Class): ka6lsw
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Owner: Kepnet Internet Services

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