diff --git a/op/op.ExtensionMgr.php b/op/op.ExtensionMgr.php
index 55dcd0177..181bcb7ce 100644
--- a/op/op.ExtensionMgr.php
+++ b/op/op.ExtensionMgr.php
@@ -45,6 +45,8 @@ else $currenttab=NULL;
 
 // add new attribute definition ---------------------------------------------
 if ($action == "download") {
+	UI::exitError(getMLText("admin_tools"),getMLText("access_denied"));
+
 	if (!isset($_POST["extname"])) {
 		UI::exitError(getMLText("admin_tools"),getMLText("unknown_id"));
 	}