Today I received the first of what I think might be a new kind of pingback spam. One which passes all the usual checks – i.e. the source site contains a link back to the post pingbacked (or at least does at the time the pingback occurs) and supports the pingback specification.
Basically what the spammers appear to be doing is creating the spammy article and then designating a paragraph at the end of the message to temporarily contain an outgoing link. They then automate the manipulation of this paragraph and the sending of pingbacks so as to get linkbacks to there article from multiple remote sites. This means that for approximately a five minute period around the time at which you receive the pingback your site is linked. Then they move onto another target and you are no longer linked but they hope are still linking back to them.
What can we do to fight against this type of pingback spam? I think a new spam rule for validating pingbacks is to ensure that the extracted pingback content contains more that just a link to your post and actually includes some texts as well. For example the following, as extracted pingback content, would be treated as possible spam:
[...] http://example.com/my-post [...]
To conteract this new kind of pingback spam I’ve hacked together a simple Spam Karma 2 plugin which gives a -5 karma hit to pingbacks containing one link as there whole content to force them into moderation (by default pingbacks get a +4 bonus as they are harder to spoof than trackbacks).
You can download the Spam Karma 2 plugin here: sk2_pjw_pingback_plugin.0.01.zip
Installing is as easy as:
- Install Spam Karma 2
- Activate Spam Karma 2
- Unzip the plugin into the
sk2_pluginsdirectory within the
SK2directory in your plugins folder. (e.g. wp-content/plugins/SK2/sk2_plugins/)