Captcha Techniques in Spam

The majority of my spam recently has involved stock recommendations encoded as an embedded GIF. Examples of some less grammatically-challenged subject lines are: “garbage can Frisbee”, “official espresso”, “noisy symmetry”, “crutch innuendo”, “fabricate hiccup” and “depraved give-and-take”.

Today I received an e-mail that illustrates how spammers are adopting image manipulation techniques used in captchas to encode their images.

capitalization-resized.

I think this is interesting as the spammers are using a technique that has previously been deployed against them (to hinder automated sign-up for free e-mail accounts and blog comment spam, for example).

Personally, I use the Qurb white list e-mail filter which does a good job of catching these messages.

4 Responses to Captcha Techniques in Spam

  1. B55's all around says:

    If the Quirb white list filter did indeed do a good job of catching your spam e-mail you wouldn’t have written this article

  2. The filtered messages are quarantined into a folder, and a pop-up is displayed which allows you to approve or block the sender.

  3. retahmaps says:

    Let’s give these guys a zillion email addresses to play with for a while … ;o)

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