Help. WebResource.axd is leading to a exploit site

I've a site hosted in a shared enviroment.

Every time I do a and add some validation controls the ASP.Net generate a script call to a WebResource.axd who leads to a exploit site:

www2.sho开发者_C百科pezlive.com/main.php?.....

How the hacker could compromise the assemblies of .Net and how can I get rid of this mess?

It was an FTP atack from a leaked password.

The hacker changed the .htaccess file and inject his malicious code.