Wordpress exposes a so called Pingback API to link to other blogposts. Using this feature you can scan other hosts on the intra- or internet via this server. You can also use this feature for some kind of distributed port scanning: You can scan a single host using multiple Wordpress Blogs exposing this API. This issue was fixed in Wordpress 3.5.1. Older versions are vulnerable, if the XML-RPC Interface is active.

http://www.acunetix.com/blog/web-security-zone/wordpress-pingback-vulnerability/

Before you start you need to install all dependencies with

gem install bundler
bundle install

Quick-scan a target via a blog:

ruby wppps.rb -t http://www.target.com http://www.myblog.com/

Use multiple blogs to scan a single target:

ruby wppps.rb -t http://www.target.com http://www.myblog1.com/ http://www.myblog2.com/ http://www.myblog3.com/

Scan a free wordpress.com blog (all ports) from the internal network:

ruby wppps.rb -a -t http://localhost http://myblog.wordpress.com/