This book constitutes revised selected papers from the 4th International Workshop on Graphical Models for Security, GraMSec 2017, held in Santa Barbara, CA, USA, in August 2017. The 5 full and 4 short papers presented in this volume were carefully reviewed and selected from 19 submissions.

Graphical modeling of Security Arguments: Current State and Future Directions.- Evil Twins: Handling Repetitions in Attack - Defense Trees - A Survival Guide.- Visualizing Cyber Security Risks with Bow-Tie Diagrams.- CSIRA: A method for analysing the risk of cybersecurity incidents.- Quantitative Evaluation of Attack Defense Trees using Stochastic Timed Automata.- Probabilistic Modeling of Insider Threat Detection Systems.- Security Modeling for Embedded System Design.- Circle of Health Based Access Control for Personal Health Information Systems.- New Directions in Attack Tree Research: Catching up with Industrial Needs.- Employing Graphical Risk Models to Facilitate Cyber-Risk Monitoring - the WISER Approach.