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Recognizing and foiling "spambots"

  • "Spambots" scan Web pages for victim addresses

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  • Most don't obey robots.txt etiquette

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  • Can often be recognized via HTTP_USER_AGENT field and rerouted to perdition via mod_rewrite... or blackholed (I'll show how to do this easily in a few slides)

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  • "Spambot-proof" your pages! Remove explicit addresses and mailto: links. Some techniques:
  • Most spambots don't understand character entities! Instead of
    • mailto:clueless@newbie.com
    write
    &#109;ailto&#58;clueless&#64;newbie&#46;&#99;om
  • Construct mailto: links on the fly with Javascript (spambots can't execute it)
  • Render address as bitmap
  • Supply link via POST method
  • Feed spambot bogus addresses
  • Use "address mangling;" e.g.

    • clueless.remove-me@newbie.com
  • For more tips, plus CGI scripts, see "Spambot Beware" (http://www.turnstep.com/Spambot/)
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