This volumecontains the paperspresented at VizSec 2008, the 5th International Workshop on Visualization for Cyber Security, held on September 15, 2008 in Cambridge, Massachusetts, USA. VizSec 2008 was held in conjunction with the 11thInternationalSymposiumonRecentAdvancesinIntrusionDetection(RAID). There were 27 submissions to the long and short paper categories. Each submission was reviewed by at least 2 reviewers and, on average, 2.9 program committee members. The program committee decided to accept 18 papers. The program also included an invited talk and a panel. The keynote address was...