Do not allow referrer to modify the sender (#3469)

http://mathiasbynens.github.io/rel-noopener/

website/source/community/index.html.md

@@ -77,10 +77,10 @@ list as contributors come and go.
 
     <img class="pull-left" src="https://www.gravatar.com/avatar/1fca64df3d7db1e2f258a8956d2b0aff.png?s=125">
     <div class="bio">
-      <h3>Ross Smith II (<a href="https://github.com/rasa" target="_blank">@rasa</a>)</h3>
+      <h3>Ross Smith II (<a href="https://github.com/rasa" target="_blank" rel="nofollow noopener noreferrer">@rasa</a>)</h3>
       <p>
 
-<a href="http://smithii.com/" target="_blank">Ross Smith</a> maintains our
+<a href="http://smithii.com/" target="_blank" rel="nofollow noopener noreferrer">Ross Smith</a> maintains our
 VMware builder on Windows, and provides other valuable assistance. Ross is an
 open source enthusiast, published author, and freelance consultant.
 </p>
@@ -92,7 +92,7 @@ open source enthusiast, published author, and freelance consultant.
 
     <img class="pull-left" src="https://www.gravatar.com/avatar/c9f6bf7b5b865012be5eded656ebed7d.png?s=125">
     <div class="bio">
-      <h3>Rickard von Essen<br/>(<a href="https://github.com/rickard-von-essen" target="_blank">@rickard-von-essen</a>)</h3>
+      <h3>Rickard von Essen<br/>(<a href="https://github.com/rickard-von-essen" target="_blank" rel="nofollow noopener noreferrer">@rickard-von-essen</a>)</h3>
       <p>
 
 Rickard von Essen maintains our Parallels Desktop builder. Rickard is an

website/source/downloads.html.erb

@@ -26,8 +26,8 @@ page_title: "Downloads"
           <a href="https://releases.hashicorp.com/packer/<%= latest_version %>/packer_<%= latest_version %>_SHA256SUMS.sig">
             verify the checksums signature file
           </a>
-          which has been signed using <a href="https://www.hashicorp.com/security.html" target="_TOP">HashiCorp's GPG key</a>.
-          You can also <a href="https://releases.hashicorp.com/packer/" target="_TOP">download older versions of Packer</a> from the releases service.
+          which has been signed using <a href="https://www.hashicorp.com/security.html" target="_blank" rel="nofollow noopener noreferrer">HashiCorp's GPG key</a>.
+          You can also <a href="https://releases.hashicorp.com/packer/" target="_blank" rel="nofollow noopener noreferrer">download older versions of Packer</a> from the releases service.
         </p>
         <p>To see what has changed in each version, please refer to the <a href="https://github.com/mitchellh/packer/blob/master/CHANGELOG.md">CHANGELOG</a>.</p>
         <p>
@@ -57,7 +57,7 @@ page_title: "Downloads"
 
     <div class="row">
       <div class="col-md-8 col-md-offset-2 poweredby">
-        <a href="https://www.fastly.com?utm_source=hashicorp" target="_TOP">
+        <a href="https://www.fastly.com?utm_source=hashicorp" target="_blank" rel="nofollow noopener noreferrer">
           <%= image_tag "fastly_logo.png" %>
         </a>
       </div>