diff --git a/phpBB/includes/acp/acp_main.php b/phpBB/includes/acp/acp_main.php
index 6a450d2765..a55cc57e9f 100644
--- a/phpBB/includes/acp/acp_main.php
+++ b/phpBB/includes/acp/acp_main.php
@@ -679,13 +679,10 @@ class acp_main
 			}
 		}
 
-		// We define the variable so we avoid redundancies
 		$config_ref = $phpbb_root_path . 'config.' . $phpEx;
-
 		if (!defined('PHPBB_DISABLE_CONFIG_CHECK') && file_exists($config_ref))
 		{
-			// World-Writable? (000x)
-			$template->assign_var('S_WRITABLE_CONFIG', (bool) (@fileperms($config_ref) & 0x0002));
+			$template->assign_var('S_WRITABLE_CONFIG', (bool) $phpbb_filesystem->is_writable($config_ref));
 		}
 
 		$this->php_ini = $phpbb_container->get('php_ini');