Redirects in webspam

I haven’t blogged much about webspam lately. Akismet kills most of it, so I’m not as annoyed.

But enter a new Wordpress installation. It took a few week for the first spam to arrive, and then I attracted a regular. Geez, that’s annoying. I hadn’t had time to do something about the spam yet, but it was starting to annoy me enough I took a closer look.

What I found was a lot of redirects to spammy sites from innocent third parties. Many of them from Bitrix installations, but judging from the URL’s, there are plenty of other susceptible redirect scripts. Here’s a sampling of code you could block in blog and forum software, and that would silently get rid of a lot of spam posts:.

external.php?url=http://
go.cgi?dest=http://
go.asp?url=http://
link.php?url=http://
links_ext.pl?http://
out.php?url=http://
rd?t=http://
redirect.cfm?trgturl=http://
redirect.php?goto=http://
redirect.php?url=http://

Another bad thing about these scripts, is that you could pick up a trojan by going to a site you thought was safe, if you didn’t notice that there was a redirect actually pointing somewhere else than the safe site the redirect script is sitting on.

3 Responses to “Redirects in webspam”

  1. Kirrus says:

    I use this plugin on every wordpress install I manage:
    http://www.hybrid6.com/webgeek/plugins/wp-spamfree

    So far, I’ve not had any (really absolutely none) since I installed it. The “blocked” counter on my dashboard keeps going up though (now at 1,135 spam comments for my personal blog)

    Hope that’s useful!

  2. JJ says:

    Hi,

    sorry for the dumb question.. but how can I block above redirects?

  3. Sven says:

    @Kirrus
    Javascript and cookies used to stop spam bots a couple of years ago, today it only stops some of the cheap spammers.

    I have one of redirect-script at one of my servers, but I have built in protection against abuse in it ;) As soon as it is used for spam or abusive use it will stop working for those url.

    I also managed a site that had a short url service, is was abused by a large spamming company. Our system stopped several thousand redirects after the url had been spammed to thousands of inocents. I was shocked that so many people still are clicking spam links in email, they are feeding the spammers money!

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