The configuration of security functions in computer networks is still typically performed manually, which likely leads to security breaches and long re-configuration times. This problem is exacerbated for modern networks based on network virtualization, because their complexity and dynamics make a correct manual configuration practically unfeasible. This article focuses on packet filters, i.e., the most common firewall technology used in computer networks, and it proposes a new methodology to automatically define the allocation scheme and configuration of packet filters in the logical topology of a virtual network. The proposed method is based on solving a carefully designed partial weighted Maximum Satisfiability Modulo Theories problem by means of a state of the art solver. This approach formally guarantees the correctness of the solution, i.e., that all security requirements are satisfied, and it minimizes the number of needed firewalls and firewall rules. This methodology is extensively evaluated using different metrics and tests on both synthetic and real use cases, and compared to the state-of-the-art solutions, showing its superiority.

Emerging technologies such as Software-Defined Networking and Network Functions Virtualization are making the definition and configuration of network services more dynamic, thus making automatic approaches that can replace manual and error-prone tasks more feasible. In view of these considerations, this paper proposes a novel methodology to automatically compute the optimal allocation scheme and configuration of virtual firewalls within a user-defined network service graph subject to a corresponding set of security requirements. The presented framework adopts a formal approach based on the solution of a weighted partial MaxSMT problem, which also provides good confidence about the solution correctness. A prototype implementation of the proposed approach based on the z3 solver has been used for validation, showing the feasibility of the approach for problem instances requiring tens of virtual firewalls and similar numbers of security requirements.

Security personalization has become a critical need for smart homes in recent years. The current approaches cannot fully satisfy this requirement of user-centered security. We propose a user-friendly approach for the automatic configuration of home security solutions through policy-based management, minimizing human interventions, and improving security usability.

Automated policy-based network security management tools represent a new research frontier to be fully explored, so as to reduce the number of human errors due to a manual and suboptimal configuration of security services. Moreover, the agility that an automated tool would require can be provided by the most recent networking technologies, Network Functions Virtualization and Software-Defined Networking, which move the network management from the hardware level to the software. However, even though a Security Automation approach is nowadays feasible and would bring several benefits in facing cybersecurity attacks, pending problems are that currently only a limited number of automatic management tools have been developed and that they do not have a direct integration with cloud orchestrators, consequently requiring human interaction. Given these considerations, in this paper we propose a novel framework, whose goal is to automatically and optimally allocate and conFigure security functions in a virtualized network service in a formal and verified way, directly integrated in cloud orchestrators. We validated this contribution through an implementation that is able to cooperate with two well-known orchestrators, that are Open Baton and Kubernetes.

Network Function Virtualization (NFV) and Software Defined Networking (SDN) are new emerging paradigms that changed the rules of networking, shifting the focus on dynamicity and programmability. In this new scenario, a very important and challenging task is to detect anomalies in the data plane, especially with the aid of suitable automated software tools. In particular, this operation must be performed within quite strict times, due to the high dynamism introduced by virtualization. In this paper, we propose a new network modeling approach that enhances the performance of formal verification of reachability policies, checked by solving a Satisfiability Modulo Theories (SMT) problem. This performance improvement is motivated by the definition of function models that do not work on single packets, but on packet classes. Nonetheless, the modeling approach is comprehensive not only of stateless functions, but also stateful functions such as NATs and firewalls. The implementation of the proposed approach achieves high scalability in complex networked systems consisting of several heterogeneous functions.

Introducing formal methods in the automatic resolution of network security management problems can guarantee solution correctness, so also boosting human confidence in using automatic techniques. A necessary step to achieve this feature is the definition of formal network models, representing network topology, traffic flows, etc. Each state-of-the-art formal network modeling approach has been proposed and validated only for a specific management problem (e.g., verification of configurations or refinement of policies into configurations). This paper analyzes a possible combination of the most promising state-of-the-art modeling approaches into a unified formal model that can be used by existing automatic resolution algorithms to solve both the verification and the refinement problems, without the need of major changes. The model is flexible enough to allow different aggregation levels of traffic into flows. The paper analyzes two opposite flow aggregation strategies, named Atomic Flows and Maximal Flows, and compares their performance when applied to the two identified security problems.