Visafi's visa bot was taking orders from the whole internet
Visafi's website is a front desk. Fill in a visa request and a second machine on AWS does the real work: a browser bot that completes the forms for you. That bot was driven by a Selenium Grid hub, and the hub was listening on port 8080, on a public IP, with no password. Remote control of real browsers, on their infrastructure, handed to anyone who found the port.