This volume contains the post-proceedings of the Second International Workshop on Critical Information Infrastructure Security (CRITIS 2007), that was held during October 3-5, 2007 in Benalmadena-Costa (Malaga), Spain, and was hosted by the University of Malaga, Computer Science Department. In response to the 2007 call for papers, 75 papers were submitted. Each paper was reviewed by three members of the Program Committee, on the basis of significance,...