Aspects of the present disclosure relate to computer system security. A machine accesses a set of records corresponding to a set of users having access to a computer system. The machine stores, for each user in the set of users, a baseline profile representing baseline activity of the user with respect to a set of data sources of the computer system. The machine monitors activity of the set of users with respect to the set of data sources. The machine determines, based on monitoring the activity of the set of users, that a user action of a specified user, with respect to one or more data sources from the set of data sources, is anomalous relative to the baseline profile of the specified user. The machine provides a digital transmission representing the anomalous user action.