Cloud Computing Security Modeling and Analysis Based on a Self-Cleansing Intrusion Tolerance Technique
Total Page:16
File Type:pdf, Size:1020Kb
Journal of Information Assurance and Security. ISSN 1554-1010 Volume 11 (2016) pp. 273-282 c MIR Labs, www.mirlabs.net/jias/index.html Cloud Computing Security Modeling and Analysis based on a Self-Cleansing Intrusion Tolerance Technique Iman EL MIR1, Dong Seong Kim2 and Abdelkrim HAQIQ3 1Computer, Networks, Mobility and Modeling laboratory FST, Hassan 1st University, Settat, Morocco [email protected] 2Department of Computer Science and Software Engineering University of Canterbury, New Zealand [email protected] 3Computer, Networks, Mobility and Modeling laboratory FST, Hassan 1st University, Settat, Morocco e-NGN Research Group, Africa and Middle East [email protected] Abstract: Nobody can deny that Cloud computing, a rapidly to perform their applications and services. Users are able developing information technology, has attired the concern of to provision cloud computing resources without requiring the whole world. However, this emergent technology is Internet- human interaction, mostly done though a web-based self- based computing, allows on demand network access to a shared service portal. However, Cloud computing provides to enter- resources, software and information where it becomes an im- prises and,to its legitimate users on demand network access portant security issue. Consequently, we must have a clear un- to applications and shared pool of computing resources with- derstanding of potential security benefits and risks associated out installation, it delivers three fundamental service models with cloud computing. Since security is increasingly the princi- [1], such as Software as a Service(SaaS), Platform as a Ser- pal concern in the conception and implementation of software vice(PaaS) and, Infrastructure as a Service(IaaS). systems, it is very important that the security mechanisms are designed so as to protect the computer systems against cyber • IaaS : the cloud providers deliver computation process- attacks. An Intrusion Tolerance Systems play a crucial role in ing, storage, networks and computing resources. Hence, maintaining the service continuity and enhancing the security the consumer can deploy and run an arbitrary applica- compared with the traditional security. In this paper, we pro- tion, which is able to support operating systems and ap- pose to combine a preventive maintenance with existing intru- plications. For instance, VMware and HP are IaaS ven- sion tolerance system to improve the system security. We use a dors. Semi-Markov Process to model the system behavior. We quan- • PaaS : is a cloud computing model that delivers applica- titatively analyze the system security using the measures such tions over the Internet on-demand. It used to reduce to as system availability, Mean Time To Security Failure and cost. customer organizations the costs which can be invested The numerical analysis is presented to show the feasibility of the on infrastructure when they are developing software ap- proposed approach. An Intrusion-Tolerant System (ITS) aims plications. Microsoft windows, Google AppEngine are to maintain a useful level of operational capability throughout some examples. ongoing cyber-attacks. The applications that are part of an ITS, especially those that provide critical services for the sys- • SaaS : is a software distribution model that providers to tems mission therefore, must survive the failures and unwanted users the possibility to access into applications through changes in the system caused by malicious acts of intruders. a single interface. So, they should just require Internet Keywords: Intrusion Tolerance, Preventive Maintenance, System connection and web browser. As an example of SaaS Availability, Cloud Computing vendors, we can list Amazon, Yahoo and Google. Cloud computing attracts different users owing to its high re- I. Introduction sources elasticity and scalability which offers important sav- ings in terms of investment and manpower. The massive us- Cloud computing is an emerging technology that allows the age of cloud resources in different domain such as data stor- central remote servers to be connected to Internet in order age, operating system, cooling has many data security and MIR Labs, USA Cloud Computing Security Modeling and Analysis based on a Self-Cleansing Intrusion Tolerance Technique 274 protection challenges. It involves potential cyber-security are described and a detailed comparison has been made in risks. For this reason, the security of network systems has re- section IV. The proposed stochastic model is presented in ceived considerable attention. The traditional security mech- section V. Section VI presents numerical analysis and dis- anisms such as firewalls and Intrusion Detection Systems cusses the limitations of the proposed approach as well as (IDS) monitor the events occurring in a computer network suggesting further research. Finally, section VII is devoted and analyze them to protect the network from malicious in- to the conclusion. cidents. IDS can detect the intrusions spreading in the net- work. But these technologies are still ineffective against un- II. Related Work known and undetected attacks and cannot guarantee that a system is absolutely intruded. To improve such limitations, Most current information systems that provide useful ser- intrusion tolerance techniques have been proposed. Intrusion vices to their legitimate users are connected to the Internet, tolerance was introduced by Fraga et al. [2]. Its main objec- and it is not obvious to successfully protect such systems tive [3] is not about how to defend or detect the intrusion, but against all threats. In this context, various researches have how to tolerate the intrusion. An intrusion tolerance system been performed on intrusion tolerance and, multiple intru- has to provide services to legitimate users of a network even sion tolerant architectures have been proposed in order to if there are attacks in the network. Bloom et al. [4] suggested guarantee high quality of services and to enhance the secu- two classes of intrusion tolerance and mitigation techniques rity. Some well-known intrusion tolerance systems are Scal- namely fault tolerance and quality of service. Fault tolerance able Intrusion-Tolerant Architecture (SITAR), Malicious and can be applied at three levels: hardware level, software level, Accidental Fault Tolerance for Internet Applications (MAF- or system level. knowing that Fault tolerance is a property TIA) [9], Self-Cleansing Intrusion Tolerance (SCIT). that provides the survivability to a system to continue op- SITAR is a framework of an intrusion tolerant architec- erating properly in the presence of malicious attacks in the ture [10], was developed as a part of the DARPA funded system and Quality of service is an important issue for intru- program called OASIS (Organically Assumed and Surviv- sion tolerance system. In order to devise an effective intru- able Information Systems). It maintains services in order to sion tolerance system, one has to first think about to provide protect COTS (Commercial Off The Shelf) servers from ex- services without degradation of quality of traffic. Hence, the ternal attacks by detecting intrusions and reconfiguring of the tolerance mechanism should be able to provide a good qual- compromised servers. MAFTIA [11] was developed in the ity of services without being interested by the attacks if they OASIS program as European project. Its architecture con- are happening in a system or not. tains several layers based on conceptual models, mechanisms A virtualization-based Intrusion Tolerant System (ITS) can and protocols for achieving tolerance. provide uninterrupted services without being seriously af- Madan et al. [12] modeled the SITAR as Semi-Markov Pro- fected by various system deficiencies and different attack in- cess (SMP) model to evaluate different security attributes of tensity [5]. The Self-Cleansing Intrusion Tolerance (SCIT) the SITAR system such as availability, integrity, and confi- uses a typical virtualization-based intrusion tolerance sys- dentiality. They suggested that the attacker behavior can be tem through its proactive recovery approach. SCIT maintains described by identifying several general probability distribu- service availability through periodic recovery and allows re- tion functions. They used a steady-state analysis to obtain moving and minimizing the effects of malicious attacks. The dependability measures such as availability and, a transient effectiveness of SCIT in terms the security and performance analysis with absorbing states to calculate security measures has been verified in the domains such as Web service sys- such as MTTSF. tems [6], DNS systems [7], and firewall systems [8]. Lim et al. [13] presented a new virtualization-based server Previous intrusion tolerance techniques have focused on cluster system using three schemes namely, simplified rota- proactive recovery approaches. In this paper, we propose tion process to minimize system overhead, exposure time ad- to use a preventive maintenance technique in addition to the justment to prevent the degradation of system performance, proactive recovery approach. For instance, if Denial of Ser- and spare server insertion to deal with heavy incoming pack- vice vulnerabilities are identified by an attacker, the attacker ets. These proposed schemes are evaluated for ubiquitous sends a large amount of data in order to violate the availabil- computing systems in order to enhance the security and to ity of the target the network. If a preventive