Patch & CVE Reference
Magento Connect Manager
Magento Connect Manager (or Magento Downloader) is standalone Magento installer to manage installation and updates of Magento Connect extensions and core Magento modules.
Typically, it is available at

Nvigating to Magento Connect Manager in Backend
It requires the same authorization as for Backend:

Login screen of Magento Downloader
For detailed instructions on using Magento Connect Manager you can refer to comprehensive Installing and Managing Magento Connect Extensions guide.
Due to recent vulnerabilities in Magento a lot of bots are trying to bruteforce admin credentials via default
Restrict access to Magento
Typically, it is available at
/downloader/ URI from root of your Magento URL and can be accessed from System > Configuration > Magento Connect > Magento Connect Manager:

For detailed instructions on using Magento Connect Manager you can refer to comprehensive Installing and Managing Magento Connect Extensions guide.
Due to recent vulnerabilities in Magento a lot of bots are trying to bruteforce admin credentials via default
/downloader/ location.Restrict access to Magento
/downloader/ to protect from bots and reduce load on your site and verify that it is well hidden with our Magento scan tool.