On behalf of the Program Committee, it is our pleasure to present to you the proceedings of the 2nd GI SIG SIDAR Conference on Detection of Intrusions & Malware, and Vulnerability Assessment (DIMVA). DIMVA is organized by the Special Interest Group Security — Intrusion Detection and Response (SIDAR) of the German Informatics Society (GI) as an annual conference that brings together experts from throughout the world to discuss the state of the art in the areas of intrusion detection, detection of malware, and assessment of vulnerabilities. The DIMVA 2005 Program Committee received 51 submissions from 18 co- tries. This represents an increase of approximately 25% compared with the n- ber of submissions last year. All submissions were carefully reviewed by at least three Program Committee members or external experts according to the cri- ria of scientific novelty, importance to the field, and technical quality. The final selection took place at a meeting held on March 18, 2005, in Zurich, Switz- land. Fourteen full papers were selected for presentation and publication in the conference proceedings. In addition, three papers were selected for presentation in the industry track of the conference. The program featured both theoretical and practical research results, which were grouped into six sessions. Philip Attfield from the Northwest Security Institute gave the opening keynote speech. The slides presented by the authors are available on the DIMVA 2005 Web site at http://www.dimva.org/dimva2005 We sincerely thank all those who submitted papers as well as the Program Committee members and the external reviewers for their valuable contributions.