diff --git a/frontend/includes/include.base.php b/frontend/includes/include.base.php
index 81b8145..74b366f 100644
--- a/frontend/includes/include.base.php
+++ b/frontend/includes/include.base.php
@@ -11,6 +11,8 @@
  * licensing text.
  */
 
+if(!isset($_CVM)) { die("Unauthorized."); }
+
 $_CPHP = true;
 require("cphp/base.php");
 require("include.exceptions.php");
diff --git a/frontend/includes/include.exceptions.php b/frontend/includes/include.exceptions.php
index c7f0f8d..120ddbb 100644
--- a/frontend/includes/include.exceptions.php
+++ b/frontend/includes/include.exceptions.php
@@ -11,6 +11,8 @@
  * licensing text.
  */
 
+if(!isset($_CVM)) { die("Unauthorized."); }
+
 class SshConnectException extends Exception {}
 class SshAuthException extends Exception {}
 class SshCommandException extends Exception {}
diff --git a/frontend/includes/include.parsing.php b/frontend/includes/include.parsing.php
index ba4547e..6e0a0e5 100644
--- a/frontend/includes/include.parsing.php
+++ b/frontend/includes/include.parsing.php
@@ -11,6 +11,8 @@
  * licensing text.
  */
 
+if(!isset($_CVM)) { die("Unauthorized."); }
+
 function split_whitespace($input)
 {
 	return preg_split("/\s+/", $input);