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technical question about spam bot filling out contact form

Discussion in 'Black Hat SEO' started by nonai, Apr 27, 2014.

  1. nonai

    nonai Power Member

    Oct 10, 2013
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    my site has been getting hundreds of spam messages through its contact form. These are the typical spam sent by bots, like "cheap oakley glasses buy cheap glasses online. have you ever wondered where to buy cheap oakley glasses online?"

    my contact form has a phone number field, and upon looking at hundreds of these messages, I noticed they all have something in common: the phone number field is filled out with a url. so using php regex, I banned letters in the phone number field. only numbers and dashes are allowed, no letters.

    if someone enters anything that doesn't look like a phone number and presses submit, the form will give an error, saying "your phone number does not seem to be valid. only numbers and dashes are allowed"

    Now, here comes the question. is this a permanent solution? or will the bots somehow "learn" what is allowed in that field, and start filling it out with numbers?
  2. ttrox

    ttrox Regular Member

    Jun 28, 2013
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    The bots will hardly learn from it. You have to understand that most bots work by the method "take it or leave it", meaning that if 1 out of 10000000 sites has that kind of validation, it's just one off from that list.

    Now, it's possible that they will get coded again taking in mind that validation, but I would bet against it.

    If you're using wordpress, there are a handful of plugins that let you use captchas to avoid this problem.
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  3. ChrisX

    ChrisX Jr. VIP Jr. VIP

    Oct 8, 2011
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    Home Page:
    Unless you have a large site and somebody modifies their bot to work with your new form, you should be fine.
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  4. partymarty4870

    partymarty4870 Elite Member

    Jul 7, 2010
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    I come from a land downunder
    I'd also add the + sign to your allowed list, as that's used in international phone numbers