diff --git a/src/applications/auth/controller/PhabricatorLoginValidateController.php b/src/applications/auth/controller/PhabricatorLoginValidateController.php
index e8b3de5045..492b47cf5f 100644
--- a/src/applications/auth/controller/PhabricatorLoginValidateController.php
+++ b/src/applications/auth/controller/PhabricatorLoginValidateController.php
@@ -28,7 +28,7 @@ final class PhabricatorLoginValidateController
 
     $failures = array();
 
-    if (!$request->getStr('phusr')) {
+    if (!strlen($request->getStr('phusr'))) {
       throw new Exception(
         "Login validation is missing expected parameters!");
     }