This book constitutes the thoroughly refereed post-proceedings of the 7th International Workshop on Critical Information Infrastructures Security, CRITIS 2012, held in Lillehammer, Norway, in September 2012. The 23 revised full papers were thoroughly reviewed and selected from 67 submissions. The papers are structured in the following topical sections: intrusion management; smart metering and grid, analysis and modeling; SCADA; cyber issues; CI analysis; CIP sectors; CI assessment; and threat modeling.