diff --git a/lib/installer.php b/lib/installer.php
index 49ba44926323c8eb6054c8cdf58ceacd911db7d1..2229559208afaf220ccd1ed22f94321a0c2d55bc 100644
--- a/lib/installer.php
+++ b/lib/installer.php
@@ -436,10 +436,28 @@ class OC_Installer{
 
 		$blacklist=array(
 			'exec(',
-			'eval('
+			'eval(',
 			// more evil pattern will go here later
-			// will will also check if an app is using private api once the public api is in place
 
+			// classes replaced by the public api
+			'OC_API::',
+			'OC_App::',
+			'OC_AppConfig::',
+			'OC_BackgroundJob::',
+			'OC_Config::',
+			'OC_DB::',
+			'OC_Files::',
+			'OC_Helper::',
+			'OC_Hook::',
+			'OC_JSON::',
+			'OC_Log::',
+			'OC_Mail::',
+			'OC_Preferences::',
+			'OC_Request::',
+			'OC_Response::',
+			'OC_Template::',
+			'OC_User::',
+			'OC_Util::',
 		);
 
 		// is the code checker enabled?