A data lake is a way to store and process large amounts of original (raw) data that is too big for a standard database. Data lakes evolved from data warehouses and removed the need to pre-transform data for it to be analysable. Rather, data lakes operate on top of low-cost blob storage and allow for scalable execution of various workloads. Security, as usual, is lagging behind in the adoption of this approach. Unlike SIEM tools initially built for managing logs, data lakes were designed to store any kind of data, structured or unstructured, at scale and in a cost-efficient manner.