Technical resource
[magento] Hundreds of new admin users with empty data after SUPEE-11314
Note: This is a historical reference, not a current security baseline. Magento 1 is end-of-life.
There are a lot of new admin users in Magento Backend at System > Permissions > Users screen after upgrade or patch: 
In `admin_user` table all fields for these users are NULL, i.e. email, username are NULL as well.
Cause
Bug in v1 version of SUPEE-11314 patch released on April 28, 2020.Solution
Magento has released v2 version of SUPEE-11314 on May 12, 2020. It is required to revert v1 and apply v2 version of SUPEE-11314 to correct this.The fix is in:
--- app/code/core/Mage/Admin/Model/Observer.php
+++ app/code/core/Mage/Admin/Model/Observer.php
@@ -133,6 +133,11 @@
{
$password = $observer->getEvent()->getPassword();
$user = $observer->getEvent()->getUser();
+ $authResult = $observer->getEvent()->getResult();
+
+ if (!$authResult) {
+ return;
+ }
if (
!(bool) $user->getPasswordUpgraded()