Data-Driven Model-Based Decision-Making - July 2015

Public Audience
Purpose: To highlight project progress. Information is generally at a higher level which is accessible to the interested public. All information contained in the report (regions 1-3) is a Government Deliverable/CDRL.

PIs: William Sanders, Masooda Bashir, David Nicol, and Aad Van Moorsel*

Researchers: Ken Keefe, Mohamad Moureddine, Charles Morriset* and Rob Cain* (Newcastle Univ., UK)

HARD PROBLEM(S) ADDRESSED
This refers to Hard Problems, released November 2012.

• Predictive Security Metrics - System security analysis requires a holistic approach that considers the behavior of non-human subsystem, bad actors or adversaries, and expected human participants such as users and system administrators. We are developing the HITOP modeling formalism to formally describe the behavior of human participants and how their decisions affect overall system performance and security. With this modeling methodology and the tool support we are developing, we will produce quantitative security metrics for cyber-human systems.
• Human Behavior - Modeling and evaluating human behavior is challenging, but it is an imperative component in security analysis. Stochastic modeling serves as a good approximation of human behavior, but we intend to do more with the HITOP method, which considers a task based process modeling language that evaluates a human's opportunity, willingness, and capability to perform individual tasks in their daily behavior. Partnered with an effective data collection strategy to validate model parameters, we are working to provide a sound model of human behavior.

PUBLICATIONS
Papers published in this quarter as a result of this research. Include title, author(s), venue published/presented, and a short description or abstract. Identify which hard problem(s) the publication addressed. Papers that have not yet been published should be reported in region 2 below.

[1] John C. Mace, Charles Morisset, and Aad van Moorsel, "Modelling User Availability in Workflow Resiliency Analysis," Symposium and Bootcamp on the Science of Security (HotSoS), April 2015.

Abstract: Workflows capture complex operational processes and include security constraints limiting which users can perform which tasks. An improper security policy may prevent certain tasks being assigned and may force a policy violation. Deciding whether a valid user-task assignment exists for a given policy is known to be extremely complex, especially when considering user unavailability (known as the resiliency problem). Therefore, tools are required that allow automatic evaluation of workflow resiliency. Modelling well-defined workflows is fairly straightforward, however user availability can be modelled in multiple ways for the same workflow. Correct choice of model is a complex yet necessary concern as it has a major impact on the calculated resiliency. We describe a number of user availability models and their encoding in the model checker PRISM, used to evaluate resiliency. We also show how model choice can affect resiliency computation in terms of its value, memory and CPU time.

ACCOMPLISHMENT HIGHLIGHTS

In this quarter, we finalized our literature review and developed an extensive survey of previous work in studying and modeling human behavior in cyber-security. We presented a poster about our work at the Symposium and Bootcamp on the Science of Security (HotSoS) where we discussed our work with several colleagues and received valuable feedback. Furthermore, we have developed a case study to evaluate our approach and obtain insight into the human behavior in cyber-security. We based our case study on the discussions presented from papers in the usable security field, as well as several recent cyber-security reports. We implemented our case study in the Mobius tool and ran several simulations. We are currently in the process of writing a paper that presents our obtained results.

For the data collection methods, we are transitioning development of algorithms to implementation of software tool support. Associated with the technical transition is a transition to a new research team. Newcastle's research associate Rob Cain has been replaced by research associate John Mace, who will work with the project for the next 12 months. During the past quarter, Aad van Moorsel and John Mace visited UIUC to attend and present at the HotSoS conference as well as spend two intensive days with the UIUC team to discuss the developed approach and plan for future steps towards development of a tool. The discussion focused on gaining an overview in terms of architectural components of the Mobius tool and the HITOP modeling language being developed to model and evaluate different characteristics of human behavior when performing daily tasks. Also had some very high-level discussion on Rob Cain's work and whether it can be adapted for simulation purposes. The resulting primary task is to gain a full understanding of the Mobius tool by working through a number of tutorials, and related papers before examining possible approaches to implementing the data collection strategies into the tool.