The main goal of this work is to analyze, discuss, and develop the theoretical foundations of the shadow digital economy, which was intensely developed in parallel with the digitalization processes of the economies of the leading countries of the world. Based on the analysis of literary sources, a definition of “shadow digital economy” (SDE) with the identification of legal, mathematical, socio-psychological and managerial approaches is proposed. Organized forms of traditional crime and their possible connection with the SDE, and the classification of actors in informational counteraction are considered. Such general features as latent nature, coverage of all phases of social production, etc. are highlighted as the basis for the functioning of the SDE, as an entrepreneurial activity. The most important feature should be considered the parasitic nature of all the processes of the SDE, including but not limited to simple actions to disclose/unauthorized change of the source code of the software product, the monetization of renting botnets and so on. The activities of some of the most prominent hacker groups are considered.