Issue #1733476 by greggles, BMDan: Fixed Make default htaccess rules protocol sensitive to avoid man-in-the-middle-attacks if users don't fully customize the rule.

.htaccess

@@ -56,6 +56,13 @@ DirectoryIndex index.php index.html index.htm
 <IfModule mod_rewrite.c>
   RewriteEngine on
 
+  # Set "protossl" to "s" if we were accessed via https://.  This is used later
+  # if you enable "www." stripping or enforcement, in order to ensure that
+  # you don't bounce between http and https.
+  RewriteRule ^ - [E=protossl]
+  RewriteCond %{HTTPS} on
+  RewriteRule ^ - [E=protossl:s]
+
   # Block access to "hidden" directories whose names begin with a period. This
   # includes directories used by version control systems such as Subversion or
   # Git to store control files. Files whose names begin with a period, as well
@@ -78,14 +85,15 @@ DirectoryIndex index.php index.html index.htm
   # To redirect all users to access the site WITH the 'www.' prefix,
   # (http://example.com/... will be redirected to http://www.example.com/...)
   # uncomment the following:
+  # RewriteCond %{HTTP_HOST} .
   # RewriteCond %{HTTP_HOST} !^www\. [NC]
-  # RewriteRule ^ http://www.%{HTTP_HOST}%{REQUEST_URI} [L,R=301]
+  # RewriteRule ^ http%{ENV:protossl}://www.%{HTTP_HOST}%{REQUEST_URI} [L,R=301]
   #
   # To redirect all users to access the site WITHOUT the 'www.' prefix,
   # (http://www.example.com/... will be redirected to http://example.com/...)
   # uncomment the following:
   # RewriteCond %{HTTP_HOST} ^www\.(.+)$ [NC]
-  # RewriteRule ^ http://%1%{REQUEST_URI} [L,R=301]
+  # RewriteRule ^ http%{ENV:protossl}://%1%{REQUEST_URI} [L,R=301]
 
   # Modify the RewriteBase if you are using Drupal in a subdirectory or in a
   # VirtualDocumentRoot and the rewrite rules are not working properly.