Sins Of The Internet: Email Spiders
Warning: this article is not for the squeamish. It contains graphic
descriptions of one of the biggest evils on the internet. If you can face
down this evil you can reduce your load of spam by several times. Hold onto
your seats and try and keep down your lunch - you are about to learn one of
the secrets of how ruthless, unethical and, well, downright evil spammers
steal your email address - and what you can do about it.
If you have access to your web site's log files, you will quickly find an
interesting phenomenon. Your site is being visited a lot more often than you
think it is. In fact, if you look closely you may be shocked to find that
your HTML files are actually being used to harm you and others. In fact, you
may be seeing the footprints left by some of the tools used by unscrupulous
spammers to steal your email addresses.
Oh wait, let me back up a bit and explain a few things. Each time you visit
a web site a record is kept of every page, graphic, sound file, video or
anything else that you access (look at or download). This record is called a
log file. Each line within the log file is one "hit" (other things are
recorded also, but that is not important to this discussion). A "hit" is
getting one "thing" from a web site. A "thing" can be an image, an HTML
page, a video, a sound file or anything else. In fact, generally when you
look at one HTML page you are actually "hitting" the web site many times,
once for each file on the page.
Each of these lines within the log file records a number of pieces of
information so that webmasters can later see what happened (don't worry,
they are not generally interested in individuals - they want to know things
like how many people are using Internet Explorer verses Netscape). One
critical piece of information is called the "user agent". Generally this
contains the browser name (Internet Explorer for example) or spider name
(googlebot, for example, is the spider for the Google search engine).
Examine these user agent fields and you will find out many interesting
facts. You will see that your site is being visited a lot more often than
you would think by lots of things with strange names:
- Slurp (used hundreds of search engines including Hotbot)
- Scooter (Altavista robot)
- Lycos Spider (used by the Lycos search engine)
- and many others as well.
Most of these are innocent 'bots, used by the major search engines to keep
their indexes up to date. These robots are very important, for they keep
your pages listed so you will get traffic. Occasionally they have other
uses, including checking your pages for changes, saving your pages for
offline browsing and various statistical functions.
You will also find some other names buried in your log files. These go by
names such as EmailSiphon and Cherry Picker. These robots are malignant and
are used by spammers to harvest email addresses. What they do is scan every
single page in your web site, as fast as they can, looking for email
addresses. Specifically, they are usually looking for "mailto:" type links.
Many websites have these kind of links. They are convenient, simple and
create a great way for visitors to send an email to someone. In fact, it's
hard to find a website which does not have email addresses embedded
somewhere within the site.
In addition, people often leave their email addresses in guestbooks, message
boards and other online communities which translate to web pages. Spam
harvesters love these types of pages, as they can get dozens, hundreds or
even thousands of different, valid and usable email addresses quickly and
How do email harvesters work? Well, some scum spammer will install one of
these programs on his system. He will tell it to begin scanning, which it
will do rapidly and efficiently. In fact, these generally scan a web site so
quickly that the server cannot do anything in the meantime (most "good"
spiders, on the other hand, limit their visits to one per second, minute or
even hour in order to allow other people and spiders to use the site while
it is being scanned).
One of the more popular email harvester programs is called EmailSiphon (a
product known as Sonic). The web site which promotes this garbage has the
following to say:
"First of its kind on the market, Sonic helps you extract highly targeted
email addresses from World Wide Web pages. Earthonline Internet marketing
expertise has enabled us to program a powerful, yet sensible product that
allows for proven focused lead harvesting. Therefore, Sonic with its search
engine ability and single domain capability is only second in World Wide Web
extraction to Earthonline Nitro."
Obviously these scumbags think they are doing a great service to the world
by providing the opportunity to scan thousands of sites per day for email
Okay, so what can you do?
Ask them politely - With most "good" spiders, this is very easy to do. You
simply create a robots.txt file or use the robots metatag (if you don't know
what those are, don't worry about it). Unfortunately, email harvesters are
written by and used by scum, so they typically ignore polite requests.
Block them - On some web servers this is possible using special commands in
a file called htaccess (again, don't worry about it if you don't know what
that is), but only with those robots that clearly identify themselves. For
those that don't tell you who they are (and some of them do not), then you
cannot block them. In addition, the web host has to be specially set up to
allow you to do this - and most, in my experience, are not.
Confuse them - Some webmasters create page after page of fake email
addresses. These pages are not intended for people or good spiders (the
robots metatag is used to keep the good one's out) but rather are made
attractive to email harvesters. The theory is simple - the harvesters will
not be able to resist the temptation (they are not very bright, as programs
go) and will scan these pages. They will grab dozens, hundreds and then
thousands of fake addresses, thus wasting the spammers time and possibly
causing their programs to crash.
Does this work? Sure - occasionally, but it also does not prevent the
spammers from getting your other email addresses, and it still chews up
resources (web servers and bandwidth) sending useless messages all over the
Cloak your email addresses - One thing you can do that is fairly effective
is to make your email addresses look like something else. Some people create
a graphic image with the email address in it (not a great solution as it
means the email address must be retyped by your visitors). Others use
(usually), but they make it difficult to maintain your site and often make
it more difficult for your visitors. In addition, presumably the spam
harvesters will eventually catch on and make their programs smarter.
Strip your site of email addresses - The only solution that works for the
present time is to remove all email addresses from all of your web pages. If
you need to get your visitors to send you information, then use a form
(these cannot be harvested by spammers as long as the email address is not
part of the form itself - Bravenet is a good service to use for this
purpose). If you don't put your email addresses directly on your site, then
the spammers cannot get it using their harvesters.
So there you have it. I hope this is of use to you in fighting this internet
evil known as email harvesting.
ABOUT THE AUTHOR
Richard Lowe Jr. is the webmaster of Internet Tips And Secrets. This
website includes over 1,000 free articles to improve your internet
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