Image Spam

Hi,

We seem to be getting a lot more spam getting through our filtering system.  These appear to be using images with text on them rather than the usual spam which is pretty much 100% removed.

We use an external company to filter spam.  I am considering using an additional filter within our network to try and remove the remaining spam.

I dont beleive it is possible to determive from an image what is spam and what isnt.  They dop appear to have long names for the images though.

Is it possible to filter on images within emails and attachments based purely on the name and length of the image name or is this asking a bit much??

Any suggestions as to what would provide the best means of filtering image spam which I beleive is going to get very much worse over time.

Would the following Linux based application be better than a Windows based software solution??

http://www.clearswift.com/products/msw/smtp_appliance/microsite/default.aspx

 
Jess
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jessmcaAsked:
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SembeeConnect With a Mentor Commented:
I am dealing with most image spam via greylisting. Doesn't stop all of it, but catches a lot. IMF has also improved lately and is catching a lot of image spam. I use IMF as one of three layers of protection.

Simon.
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jessmcaAuthor Commented:
We are using Exchange 2003 with an external filter company.  No emails arrive at the exchange server except from our filter company.

More or less no spam gets through except for these new breed using images only instead of text.

Jess
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Stacy SpearPresident/Principal ConsultantCommented:
This is a constant and never ending battle. Blocking image only mails is easy. Blocking mails with specific src codes also easy. But the spammers change their patterns and now I have 10 different spam filters looking only for images, and yet they still slip through. SPAM is a moving target!

We are moving to converting all mails to text as a result.
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Stacy SpearConnect With a Mentor President/Principal ConsultantCommented:
I have 2 IronPort C60s using a whole battery of tests. Reverse DNS, reputation filters, etc. Stops 90% of the crap. My custom filters raise that another 7-8%. What gets through is almost 100% image spam. Write new filters about twice a month to deal with new signatures. But the Army has decided to just convert all mails to text now. I think it is too broad a sword, but not every org has the tools, experience, and expertise we have.
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