A denial-of-service attack is any attempt to interrupt or inflict downtime upon IT systems, but a basic DoS threat is smaller in scale than its DDoS counterpart. With the former, the influx of traffic may come from a single source, while in a DDoS attack, traffic comes from numerous sources – making it more difficult to deal with.

During an audit a few years ago, I revealed to the client’s security team that corporate payroll information on every employee, including the CEO, was being archived in an output queue (called PAYROLL) for weeks at a time. Due to poor configuration, this information was accessible to every employee.