iis – SSRF – Internal network surfing

If an IIS web server exposes a site in INTERNET, is it possible for an attacker to access internal sites by simply modifying the host header of initial request to internet site and refer another host name of internal site ?

GET http://site1.com/ HTTP 1.1
Host: site2.intranet

Through the above request, is it possible for an attacker to get content from the intranet site ?