Towards a Layered Architectural View for Security Analysis in SCADA Systems

Supervisory Control and Data Acquisition (SCADA) systems support and control the operation of many critical infrastructures that our society depend on, such as power grids. Since SCADA systems become a target for cyber attacks and the potential impact of a successful attack could lead to disastrous consequences in the physical world, ensuring the security of these systems is of vital importance. A fundamental prerequisite to securing a SCADA system is a clear understanding and a consistent view of its architecture. However, because of the complexity and scale of SCADA systems, this is challenging to acquire. In this paper, we propose a layered architectural view for SCADA systems, which aims at building a common ground among stakeholders and supporting the implementation of security analysis. In order to manage the complexity and scale, we define four interrelated architectural layers, and uses the concept of viewpoints to focus on a subset of the system. We indicate the applicability of our approach in the context of SCADA system security analysis.Comment: 7 pages, 4 figure

ZigBee/ZigBee PRO security assessment based on compromised cryptographic keys

Sensor networks have many applications in monitoring and controlling of environmental properties such as sound, acceleration, vibration and temperature. Due to limited resources in computation capability, memory and energy, they are vulnerable to many kinds of attacks. The ZigBee specification based on the 802.15.4 standard, defines a set of layers specifically suited to sensor networks. These layers support secure messaging using symmetric cryptographic. This paper presents two different ways for grabbing the cryptographic key in ZigBee: remote attack and physical attack. It also surveys and categorizes some additional attacks which can be performed on ZigBee networks: eavesdropping, spoofing, replay and DoS attacks at different layers. From this analysis, it is shown that some vulnerabilities still in the existing security schema in ZigBee technology.Les xarxes de sensors tenen moltes aplicacions en el control i la monitorització de les propietats del medi ambient, com ara el so, l¿acceleració, la vibració i la temperatura. A causa dels limitats recursos en la capacitat de càlcul, la memòria i l'energia són vulnerables a molts tipus d'atacs. L'especificació ZigBee basada en l'estàndard 802.15.4, defineix un conjunt de capes, adaptada específicament per a xarxes de sensors. Aquestes capes suporten missatgeria segura mitjançant criptografia simètrica. Aquest article presenta dues formes diferents per agafar la clau de xifrat en ZigBee: atac a distància i atacs físics. També les enquesta i classifica alguns atacs addicionals que es poden realitzar en les xarxes ZigBee: espionatge, falsificació, reproducció i atacs DoS en les diferents capes. A partir d'aquesta anàlisi, es demostren algunes vulnerabilitats existents en l'esquema de seguretat en tecnologia ZigBee.Las redes de sensores tienen muchas aplicaciones en el control y la monitorización de las propiedades del medio ambiente, como el sonido, la aceleración, la vibración y la temperatura. Debido a los limitados recursos en la capacidad de cálculo, la memoria y la energía son vulnerables a muchos tipos de ataques. La especificación ZigBee basada en el estándar 802.15.4, define un conjunto de capas, adaptada específicamente para redes de sensores. Estas capas soportan mensajería segura mediante criptografía simétrica. Este artículo presenta dos formas diferentes para coger la clave de cifrado en ZigBee: ataque a distancia y ataques físicos. También las encuesta y clasifica algunos ataques adicionales que se pueden realizar en las redes ZigBee: espionaje, falsificación, reproducción y ataques DoS en las diferentes capas. A partir de este análisis, se demuestran algunas vulnerabilidades existentes en el esquema de seguridad en tecnología ZigBee

Identifying Security-Critical Cyber-Physical Components in Industrial Control Systems

In recent years, Industrial Control Systems (ICS) have become an appealing target for cyber attacks, having massive destructive consequences. Security metrics are therefore essential to assess their security posture. In this paper, we present a novel ICS security metric based on AND/OR graphs that represent cyber-physical dependencies among network components. Our metric is able to efficiently identify sets of critical cyber-physical components, with minimal cost for an attacker, such that if compromised, the system would enter into a non-operational state. We address this problem by efficiently transforming the input AND/OR graph-based model into a weighted logical formula that is then used to build and solve a Weighted Partial MAX-SAT problem. Our tool, META4ICS, leverages state-of-the-art techniques from the field of logical satisfiability optimisation in order to achieve efficient computation times. Our experimental results indicate that the proposed security metric can efficiently scale to networks with thousands of nodes and be computed in seconds. In addition, we present a case study where we have used our system to analyse the security posture of a realistic water transport network. We discuss our findings on the plant as well as further security applications of our metric.Comment: Keywords: Security metrics, industrial control systems, cyber-physical systems, AND-OR graphs, MAX-SAT resolutio

A virtual actuator approach for the secure control of networked LPV systems under pulse-width modulated DoS attacks

In this paper, we formulate and analyze the problem of secure control in the context of networked linear parameter varying (LPV) systems. We consider an energy-constrained, pulse-width modulated (PWM) jammer, which corrupts the control communication channel by performing a denial-of-service (DoS) attack. In particular, the malicious attacker is able to erase the data sent to one or more actuators. In order to achieve secure control, we propose a virtual actuator technique under the assumption that the behavior of the attacker has been identified. The main advantage brought by this technique is that the existing components in the control system can be maintained without need of retuning them, since the virtual actuator will perform a reconfiguration of the plant, hiding the attack from the controller point of view. Using Lyapunov-based results that take into account the possible behavior of the attacker, design conditions for calculating the virtual actuators gains are obtained. A numerical example is used to illustrate the proposed secure control strategy.Peer ReviewedPostprint (author's final draft

Solutions and Tools for Secure Communication in Wireless Sensor Networks

Secure communication is considered a vital requirement in Wireless Sensor Network (WSN) applications. Such a requirement embraces different aspects, including confidentiality, integrity and authenticity of exchanged information, proper management of security material, and effective prevention and reaction against security threats and attacks. However, WSNs are mainly composed of resource-constrained devices. That is, network nodes feature reduced capabilities, especially in terms of memory storage, computing power, transmission rate, and energy availability. As a consequence, assuring secure communication in WSNs results to be more difficult than in other kinds of network. In fact, trading effectiveness of adopted solutions with their efficiency becomes far more important. In addition, specific device classes or technologies may require to design ad hoc security solutions. Also, it is necessary to efficiently manage security material, and dynamically cope with changes of security requirements. Finally, security threats and countermeasures have to be carefully considered since from the network design phase. This Ph.D. dissertion considers secure communication in WSNs, and provides the following contributions. First, we provide a performance evaluation of IEEE 802.15.4 security services. Then, we focus on the ZigBee technology and its security services, and propose possible solutions to some deficiencies and inefficiencies. Second, we present HISS, a highly scalable and efficient key management scheme, able to contrast collusion attacks while displaying a graceful degradation of performance. Third, we present STaR, a software component for WSNs that secures multiple traffic flows at the same time. It is transparent to the application, and provides runtime reconfigurability, thus coping with dynamic changes of security requirements. Finally, we describe ASF, our attack simulation framework for WSNs. Such a tool helps network designers to quantitatively evaluate effects of security attacks, produce an attack ranking based on their severity, and thus select the most appropriate countermeasures