The presentation will describe methods for discovering interesting and actionable patterns in log files for security management without specifically knowing what you are looking for. This approach is different from "classic" log analysis and it allows gaining an insight into insider attacks and other advanced intrusions, which are extremely hard to discover with other methods. Specifically, I will demonstrate how data mining can be used as a source of ideas for designing future log analysis techniques, that will help uncover the coming threats. The important part of the presentation will be the demonstration how the above methods worked in a real-life environment.