Security researcher Giovanni Collazo was able to harvest 8781 passwords, 650 AWS access keys, 23 secret keys, and 8 private keys. First, he ran a query on the hacker search engine Shodan that returned around 2300 servers running etcd database. Then, he ran a simple script that gave him the login credentials stored on these servers which can be used to gain access to CMSs, MySQL, and PostgreSQL databases, etc.
Source: How “Hacker Search Engine” Shodan Caught Leakage of 750MB Worth Of Server Passwords