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TimJim
Joined: 20 Feb 2007
Posts: 2
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 Posted: Tue Feb 20, 2007 10:09 am Post subject: Graphical Spam |
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The latest news for the 2.0 beta 1 says:
"The classification algorithm is updated for better filtering the graphical spam."
In which way is graphical spam treated? Are there any algorithms for text recognition (OCR) of the graphics?
My bayesian Filter have been working fine until the increasing appeareance of spam in graphics with the combination of random plain-text, so that the filter can't recognize any typical spam key words. |
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vetaltm
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Joined: 05 Feb 2006
Posts: 751
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| Posted: Tue Feb 20, 2007 11:59 am Post subject: Re: Graphical Spam |
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| TimJim wrote: | The latest news for the 2.0 beta 1 says:
"The classification algorithm is updated for better filtering the graphical spam."
In which way is graphical spam treated? Are there any algorithms for text recognition (OCR) of the graphics?
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The OCR is not yet ready. But in short, the new version of classification algorithm uses an assumption that it is easier to find the differences between graphical spam and graphical good messages, than between graphical spam and all good messages. As a result the new algorithm shows better confidence and classifies with high probability more spam messages with a picture and a bunch of unlinked text. Sometimes the spam messages contain almost no text and an image, linked to some site. There is a new option for these cases, allowing blocking such messages if an image is linked to some domain, which is not the originating domain of the message. In most cases the clickable images, pointing to some different server, are used in spam. If some good services (mailing lists) will use this trick, then it is possible to whitelist their email addresses. |
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TimJim
Joined: 20 Feb 2007
Posts: 2
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| Posted: Wed Feb 21, 2007 3:30 pm Post subject: Re: Graphical Spam |
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| vetaltm wrote: | | The OCR is not yet ready. But in short, the new version of classification algorithm uses an assumption that it is easier to find the differences between graphical spam and graphical good messages, than between graphical spam and all good messages. As a result the new algorithm shows better confidence and classifies with high probability more spam messages with a picture and a bunch of unlinked text. |
Hm... well I'm not so much into this matter as you. Well, actually I'm not into this at all 
But just trying to think logically I can't really see, why an intelligent spammer shouldn't be able to create an graphical spam, which seems exactly as if a normal email contact creates an email with a non-spam graphic. How should the filter recognize this, if it doesn't analyse the text inside the graphics? Or are there differences which the spammer can't avoid technically?
| vetaltm wrote: | | Sometimes the spam messages contain almost no text and an image, linked to some site. There is a new option for these cases, allowing blocking such messages if an image is linked to some domain, which is not the originating domain of the message. In most cases the clickable images, pointing to some different server, are used in spam. If some good services (mailing lists) will use this trick, then it is possible to whitelist their email addresses. |
But I've seen now a bunch of graphical spam, without any link but a textual explanation inside the graphic on how to get to the webpage ("put into your browser's adress bar the url ... etc."). |
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usman124
Joined: 11 Sep 2013
Posts: 1
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| Posted: Wed Sep 11, 2013 5:43 am Post subject: |
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| erences between graphical spam and graphical good messages, than between graphical spam and all good messages. As a result the new algorithm shows better confidence and classifies with high probability more spam messages with a picture and a bunch of unlin |
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