From Trusted Cloud Infrastructures to Trustworthy Cloud Services

Transcription

1 From Trusted Cloud Infrastructures to Trustworthy Cloud Services Michael Gröne. Norbert Schirmer Sirrix AG security technologies Im Stadtwald, Geb. D3.2, Saarbrücken, Germany {m.groene Abstract Trustworthy Cloud services may only be built upon a strong basis of a Trusted Cloud. Such trusted infrastructures are also needed to reach IT security compliance in enterprises. The cloud model of Infrastructure as a Service (IaaS), combined with the trusted components proposed in this paper and researched in actual EU and Germany-wide cloud computing projects is a big chance for higher security in enterprises, especially for SMEs. We describe two current projects that reflect these topics and the associated security work packages to develop mechanisms and technologies for future-oriented isolation of security domains and information flow control. These are Trustworthy Clouds (TClouds) at EU level and Emergent in Germany as part of the Software-Cluster project. The overall solution resulting from research and development done in both projects is one that establishes security guarantees on the data stored by enterprise platforms on infrastructure clouds and cloud services without affecting the enterprise workflows. An innovative use case in the home healthcare sector demonstrates how future cloud infrastructures and services may look like. 1 Cloud Computing, Security and Trust Over the past years there has been much written and told about Cloud Computing, a applicable definition was given by NIST in 2011 [DrMe11]. Cloud services promise the needs-based distribution of IT infrastructures, platforms and services through standardized interfaces on the web. A pay-per-use model is given and the resources scale to the needs of their users, both to save IT costs. Fixed investments for an in-house IT are replaced by variable costs, a rigid in-house IT infrastructure gives way to flexible and dynamic services. Even if these characteristics fit perfectly into today s fast moving and flexible business processes, there are a number of problems that hinder wide adoption of public Cloud Computing in enterprise environments, in particular that are IT security concerns. On the other side requirements for cost savings and flexibility, especially in small and mediumsized enterprises (SMEs), are the factors driving forward the overall use of public cloud services. From an IT security perspective the main requirement is to reach at least the same security level as it should be in a local infrastructure combined with new security requirements resulting from the new risks of outsourcing the infrastructure to cloud providers.

2 2 From Trusted Cloud Infrastructures to Trustworthy Cloud Services 1.1 Cloud as a Chance for Higher Security in SMEs Our thesis is that Cloud Computing is a distinctive chance for improving IT security in SMEs. When looking at today s SMEs with 200-1,000 employees, IT security is in fact an infrastructure topic, not a business driven one. For this reason, compliance is nearly absent. In today s IT infrastructures there are strong needs for information flow control rather than traditional access control policies. Current examples of hacking attacks on the NATO or the German federal police and reports of massive attacks worldwide such as Operation Shady RAT [Alpe11] show that. If infrastructure security is part of the cloud service an SME definitely may reach higher security and reach compliance with existing enterprise security policies. Moreover, this helps SME with collaboration with partners, e.g. when working together on confidential data. A significant increase of IT security compliance, driven by Cloud Computing, is foreseeable, especially in SMEs. There are projects which contribute to reach that goal. 1.2 New technology; new risks Privacy and security concerns pose a significant risk towards the new technology used for Cloud Computing. The attacker model of public cloud computing has significantly changed compared to the one in an enterprise domain (usually protected by firewalls, gateways, etc.). Cloud administrators may access customer data; everyone may access services available to the public Internet. Therefore, confidential information must be protected against cloud insiders as well as other customers. Simple authentication mechanisms of cloud users only by username and password are too weak to protect against brute force attacks, which could be issued by literally anybody, and attacks as mentioned above, such as stealing of password-databases. One essential type of service supported by public clouds is Infrastructure as a Service (IaaS), which allows providing virtual infrastructures, such as virtual machines, network, or storage. However, holistic security policies and the enforcement of those policies on these resources are often unclear. In the Software as a Service (SaaS) model of cloud computing, due to the functionality and characteristics of the applications used, data is processed in plain text (regardless if it is stored encrypted or not). Without further means cloud service providers or their subcontractors may easily use customer information for their own purposes. Security guarantees expected by business-critical and privacy-sensitive applications and infrastructures are often missing, leaving IT security experts and lawyers to advice that confidential information or critical data should not be stored on a public cloud. In particular, initially the users have to gain trust in an equally secure and legally compliant processing of sensitive user data by the cloud vendors. Several security-related reports such as ENISA s Cloud Computing - Benefits, risks and recommendations for information security [CaHo09] were published to address those concerns. At the same time Cloud Computing services offer tremendous opportunities for progress in IT security towards trustworthy IT and compliance. Now, Cloud Computing is reality and first experiences from the currently largest EU and Germany-wide Cloud Computing projects with major activities focussing on security and trust are introduced in this paper.

3 From Trusted Cloud Infrastructures to Trustworthy Cloud Services The Projects TClouds and Emergent The project Trustworthy Clouds (TClouds) - Privacy and Resilience for Internet-scale Critical Infrastructure [TClo11] started in October 2010 and has a running time of over three years. It is funded by the European Commission. With 7.5 million euros in funding, TClouds is targeting the development of a secure, highly reliable and privacy-compliant cloud infrastructure. The well-balanced Consortium consists of 14 partners from seven different countries, including IBM, Philips, EDP and Sirrix AG. Launched in July 2010, Emergent, a sub-project of the Software-Cluster [Soft11], is funded by the German Federal Ministry of Education and Research, with 39 companies, including SAP, Software AG, Sirrix AG, John Deere, academic institutions and other actors in a region, a running time of over five years and up to 40 million euros in funding. The participants are targeting research and development of fundamentals for emergent software to build up future business software by using trustworthy cloud services and secure information flows between federated domains. We share our experiences in trustworthy Cloud Computing and innovative research results out of both projects focused on our topics and the components we are involved in as part of the projects security work packages. Below we illustrate an example cloud scenario and identify the requirements of Trusted Cloud Computing, show integration of internal IT infrastructures into a trusted cloud infrastructure and our topics in the projects, present an example use case out of the TClouds project, give an outlook onto future work and a conclusion which completes our paper. 2 Cloud Scenario, Requirements and Mechanisms The common Cloud Computing scenario means outsourcing of IT infrastructures, such as servers and storage. Those systems are running in datacenters off-premise. Due to outsourcing the risk of a malicious insider at the cloud provider, e.g. a cloud admin, is a core threat to be tackled. In Cloud Computing the basic model is IaaS, which involves virtual infrastructures that are owned by cloud providers. Virtual infrastructures consist of virtual machines (VMs), virtual networks and virtual storage. Users of the IaaS cloud type could benefit in the way of scalability, availability and resilience, increased connectivity and pervasive reachability and cost reduction. Customers require isolation from other customers, which may be competitors. They need strict isolation of servers and data. This is traditionally ensured by physical isolation of virtual infrastructures. Datacenter providers, such as IBM, HP and other providers encapsulate every virtual infrastructure on physical isolated server clusters, storage and network infrastructures (cf. Fig. 1).

4 4 From Trusted Cloud Infrastructures to Trustworthy Cloud Services Fig. 1: Physically isolated virtual environments in a datacenter Today, such usage of datacenters is also referred to as private Cloud Computing. Since resources are dedicated to customers and cannot be transparently scaled on users demands private Cloud Computing is not as far as effective and scalable as public Cloud Computing is. As a matter of fact physical isolated virtual infrastructures are often too expensive for SME customers. Public cloud IaaS is used as a more efficient and therefore much cheaper solution to fulfil customer needs for outsourcing of IT infrastructures. Here all customers share the same resources. Fig. 2: Classical public cloud provider Infrastructure as a Service (IaaS)

5 From Trusted Cloud Infrastructures to Trustworthy Cloud Services 5 This scenario and its challenges result in an increasing need to devise effective approaches taking advantage of cloud infrastructures to reach effectiveness and scalability of a public cloud without compromising security requirements (especially isolation) and trust assumptions like in a private cloud. The central security requirements for security are: 1. Segregation of duties: the Cloud administrator is only responsible to manage the cloud resources whereas the organization administrator (of the customer) is responsible for the organisations security policy 2. Isolation: strong isolation between customers as well as the cloud administrators is needed to ensure confidentiality of the customer s data. 3. Verifiability of the platform: as the cloud platform is off-premise of the customer we demand technical means to ensure its integrity beyond audits, certification or SLAs. We address those requirements by explaining how current research and development on a trusted infrastructure solution, including server, network and management, can provide interfaces to the cloud, such that data processed and stored on the cloud and flowing between cloud services in different security domains is seamlessly encrypted as it leaves a security domain defined by the enterprise. We start by building the foundation of a Trusted Cloud right into the servers by employing a trusted hardware anchor which is capable of integrity checking and remote attestation. We build on it as a piece of hardware which measures the other hardware and software of the server during booting to ensure the integrity of the server. Moreover, via remote attestation the hardware anchor can be used to verify the integrity of the server towards a remote party (the customer or a management service). The core piece of software the hardware anchor has to check is the security kernel [HASK08] and the hypervisor as a part of it. The security kernel is used to enforce our isolation requirements. It is responsible to encrypt the data of the customers as it is stored. During computation the data in the VMs is processed in plain text. The hypervisor isolates the VMs from each other but can itself access all the memory within the VMs. To secure the hypervisor being abused by a cloud administrator to peek into the VMs of customers we propose that the API of the hypervisor has to be tamed by the security kernel. The kernel should only offer a limited API (e.g. to start, stop and migrate VMs) but not to dump the memory of VMs. With such a management API in place there is no need for an almighty root account for administrators. The management can be done remotely via a trusted cloud management component using this API. The hardware anchor of the servers and the management component can be employed to build a trusted channel (encrypted, mutually authenticated and mutually integrity checked) between the management component and the servers. This scenario is depicted in Fig. 3.

6 6 From Trusted Cloud Infrastructures to Trustworthy Cloud Services Fig. 3: Example of a Trusted Cloud Provider As the hardware anchor Trusted Computing technology as proposed by the Trusted Computing Group [TCG11] could be used, e.g., the Trusted Platform Module (TPM) [TPM11]. 3 Integration of Internal IT Infrastructure Once such a trusted cloud infrastructure is available, one can go one step forward and not only isolate different customers but also push isolation principles into the organizations of the customers. Within an organization, there are typically different departments, like human resources, accounting, development and customer relations. These have different security requirements on the data they process, reaching from personal data to company secrets. These security domains should be kept separate and information flows between them should be strictly controlled. This concept is known as Trusted Virtual Domains (TVDs) [GJP+05]. Trusted Virtual Domains build an isolated virtual infrastructure on shared resources and thus fit into the cloud computing paradigm. Among the strengths of TVDs is the transparent data protection and enforcement of information flow policies - platforms and users logically assigned to the same TVD can access distributed data storage, network services, and remote servers without executing any additional security protocols, while resources belonging to different TVDs are strictly separated. Those resources remain inaccessible for unauthorized participants. Information flows between TVDs are only allowed if they confirm to the security policy of the organisation. TVDs are realized by the same means as described above for the trusted cloud

7 From Trusted Cloud Infrastructures to Trustworthy Cloud Services 7 infrastructure: TPMs as a hardware anchor and for remote attestation, a secure hypervisor and a security kernel to govern isolation and information flows between TVDs and a central management component to manage the security policies. The only difference is, that the management component for the organisation s internal TVDs should be controlled by the customer himself and not by the cloud provider. This management component acts as an interface between the organization s internal IT infrastructure and the cloud services. All devices from mobile phones to laptop and desktop computers as well as on-premise serves which access the TVDs in the cloud also have to be part of the same TVD security mechanisms and management. Only then a coherent end-to-end security can be guaranteed. As mentioned in Section 1, current examples of hacker attacks [Alpe11] show that infecting and remote controlling end users desktops is an important goal for attackers. So, being able to use full functional and still usable TVDs on a desktop-level is another building block in enabling SMEs to reach compliance with IT security policies. Since resources always remain inaccessible for unauthorized participants, even data that is stored on mobile storage devices is automatically protected by encryption. Those data can only be decrypted within the same TVD the device has been assigned to. Hence, users cannot forget to employ encryption, and data on flash drive cannot be used outside the TVD. A Trusted Desktop solution as depicted in Fig. 4 supporting a Trusted Cloud, centrally managed by a trusted management component should complete the whole picture of a continuous secure and trustworthy cloud infrastructure. This is a first step towards continuous trustworthy infrastructures and services. Fig. 4: Trusted Platforms at the Endpoints TrustedDesktop

8 8 From Trusted Cloud Infrastructures to Trustworthy Cloud Services In Fig. 5 such an integrated infrastructure is depicted. The Trusted Organization Manager is in charge to manage the internal infrastructure as well as to push the security policy to the Trusted Cloud Management Component which itself pushes the information to the Trusted Servers. The chain of trust is maintained by mutually ensuring the integrity of all trusted components via remote attestation and communicating via trusted channels. On the organisations side we exemplified the devices by a Trusted Desktop. As desktop virtualization is already commonly used today (e.g. to simultaneous use Windows and Linux programs on the same desktop or even laptop), the same architecture as described for the Trusted Server can be used. As [FGSS11] shows this also extends to mobile devices. Fig. 5: Internal Infrastructure, Trusted Virtual Domains and Central Management 4 Example Project Use Case In this section, a home healthcare use case motivate how future cloud services may look like and why innovative security, trust mechanisms and functionality of a Trusted Cloud as shown before are needed. 4.1 Home healthcare Healthcare services are used in the cloud for several years now (e.g. several examples could be found in the U.S.) but many security and privacy related requirements such as privacy management, where the patient will be able to configure his privacy settings for deciding who can access his data, are not in place by now. Empowering patients, allowing a continuous home-monitoring and improving links between health professional and patients will have a significant impact in patient management. In a home healthcare system IaaS is used rather than having dedicated IT infrastructure within the hospital. Most of the entities involved in such a system are relatively static. Flows of informa-

9 From Trusted Cloud Infrastructures to Trustworthy Cloud Services 9 tion do not change dynamically. The hospital can define interfaces accessible to different entities within its operations. For example, they can host a drug inventory system and configure it to be accessible to its pharmacy department or a patient registry system that is accessible to the registry staff. The cloud provider specifies well defined interfaces into the virtual infrastructure. One example of a home healthcare application using such interfaces may be a drug therapies management service, used for drug prescription and anonymous drug delivery, improving compliance with doctors recommendations. Other involved services could be a patient management portal and a personal diary. All those services need information flows between different organizational and security domains with different security and privacy related requirements. Therefore isolation mechanism and information flow control through policies and enforcement in a trusted security service are designed. Here we show that in the scenario were depressed patients need home healthcare services, able to early identify, counter fight and prevent potentially dangerous situations. The current treatment model, consisting in monthly periodic visits, is not sufficient to cope with these needs. Innovative personal wearable and non-wearable devices, such as from TClouds partner Philips, may be used to help patients and doctors to monitor and identify predefined situations through a health management application of an health and wellness service which has special interfaces for those new devices. A physical activity monitoring service provides a monitoring system that collects and analyse data from those devices. Data can be inserted directly by patient s device, the patients, or by a Physical Activity Service Provider (cf. [DPNB11], Fig. 6). So, two use cases of this scenario may be: Patient uploads her activity data from activity monitoring devices to the Physical Activity Service Provider. Physical Activity Service Provider receives data from the patient monitoring devices, analyse it and provide relevant advice to the patient. TVDs may be used here as the preferred isolation mechanism as described in Sections 2 and 3. This result in a TVD-based Trusted Cloud Infrastructure, servers and data are always isolated.

10 10 From Trusted Cloud Infrastructures to Trustworthy Cloud Services Fig. 6: Architecture of a home healthcare system (ongoing work of the TClouds project partners)

11 From Trusted Cloud Infrastructures to Trustworthy Cloud Services 11 5 Outlook / Future Work In this paper we focused on how to build trusted cloud infrastructures by employing trusted computing technologies. Both projects shown above and its activities consist of much more mechanisms, techniques, components and use cases as presented here. In TClouds a Clouds-of-Clouds middleware is developed to further improve the resilience by replicating data and computation among several clouds provided by different vendors.with Dep- Sky [BCQ+11] the TClouds Project has developed a first prototype for resilient storage building on the Cloud-of-Clouds paradigm. In the TClouds use cases of home health care and Smart Lighting the stakeholders and services are statically known. The information flows do not change in a dynamic way. In the Emergent project however, the use case of an urban management scenario exemplifies a fast and dynamically changing system and aims at coherent ad hoc service composition. Such a scenario is in need of many different security policies covering different aspects of the compound service. One major goal of the security activity in Emergent is to build a Policy Language Toolkit. TVD-based security policies and information flow policies will be part of this. 6 Conclusion Trusted Cloud Computing aims at a Future Internet where federations of standardized resilient and privacy-protecting infrastructure clouds offer virtualized computing, communication, and storage resources that allow hosting of critical and non-critical systems worldwide. Realizing this vision focuses on technological aspects, such as open standards and privacy frameworks. Security and privacy concerns pose a significant risk towards todays IT infrastructures and services, and also to Cloud Computing, but at the same time they offer tremendous opportunities for businesses to provide solutions and services in order to make Cloud Computing and thereby enterprises secure and to protect the privacy of users. For instance, Forrester Research expects cloud security to grow into a $1.5 billion market and to approach 5 % of the overall IT security spending by 2015 [Penn10]. While today encryption and identity management represent the largest segment of this market, particular growth can be expected in three directions: securing commercial clouds to meet the requirements of specific market segments highly customized secure private clouds a new range of providers offering cloud security services to add external security to public clouds. Critical infrastructures of the future, such as Smart Grids, intelligent power distribution and management, or Smart Lighting are use cases Trusted Cloud Computing is aiming at. Consisting of a multitude of distributed nodes, networked based on the IP protocol, Smart Grids will benefit from existing, mature technology and proven mechanisms. Cloud Computing technology is seen as an enabler for Smart Grids or at least dramatically improves its usability and performance. Using Cloud Computing is a requirement to be met to reach new business models, flexibility and cost-savings in Smart Grids. However, such an undertaking should not be adopted blindly without thinking about consistently implemented IT security.

12 12 From Trusted Cloud Infrastructures to Trustworthy Cloud Services In the future, even more and more mobile and autonomous entities are accessing the cloud, so the concept of TVDs should be used on mobile user devices, such as smartphones and tablets as well as the cloud services. Then a coherent level of security can be guaranteed. The overall solution resulting of research and development done in both projects introduced in this paper is one that establishes security guarantees on the data stored by enterprise platforms on infrastructure clouds and cloud services. This is designed and realized without affecting the enterprise workflows and builds up trust in public cloud services. From our point of view the main goals for success of Cloud Computing related to IT security are: 1. Strong authentication (of each entity) 2. Secure virtualization (strong isolation) 3. Trusted platforms (reliable integrity verification) Most of today s so called hacker attacks have shown that authentication by username and password is unsecure, especially in the Internet where public cloud services are within reach of everyone. So strong authentication, which means multi-factor, cryptographic authentication, is a requirement to be reached when using cloud computing. A trustworthy virtualization allows strong isolation of IT-systems, data and information which are belonging to different stakeholders/organizations. Trusted platforms allow companies a reliable integrity verification of cloud platforms. Trust in possibly false pretences of cloud providers or certificates gets a minor matter. Acknowledgements We thank all TClouds partners for substantial and very helpful input to our section, especially the authors of [DPNB11] for input and the picture of the home healthcare architecture. This research has been partially supported by the TClouds project ( eu) funded by the European Union s Seventh Framework Programme (FP7/ ) under grant agreement number ICT The work presented in this paper was partially performed in the context of the Software-Cluster project EMERGENT ( It was partially funded by the German Federal Ministry of Education and Research (BMBF) under grant no. 01IC10S01. The authors assume responsibility for the content. References [Alpe11] Alperovitch, Dmitri: Revealed: Operation Shady RAT, McAfee Labs, Available online at: [BCQ+11] Bessani, Alysson; Correia, Miguel; Quaresma, Bruno; André, Fernando; and Sousa, Paulo: Dep- Sky: dependable and secure storage in a cloud-of-clouds. In Proceedings of the sixth conference on Computer systems (EuroSys 11). ACM, New York, NY, USA, 2011, p [CaHo09] Catteddu, Daniele; Hogben, Giles: Cloud Computing - Benefits, risks and recommendations for information security, European Network and Information Security Agency (ENISA), Available online at:

13 From Trusted Cloud Infrastructures to Trustworthy Cloud Services 13 [DPNB11] Deng, Mina; Petkovic, Milan; Nalin, Marco; Baroni, Ilaria (Philips Research Europe, The Netherlands; Scientific Institute Hospital San Raffaele, Italy), 2011 IEEE CLOUD international conference, 2011 [FGSS11] Feldmann, Florian; Gnaida, Utz; Stüble, Christian; Selhorst, Marcel: Towards A Trusted Mobile Desktop. Proceedings of the 3rd International Conference on Trust and Trustworthy Computing (TRUST 10), 2010 [GJP+05] Griffin, John Linwood; Jaeger, Trent; Perez, Ronald; Sailer, Reiner; van Doorn, Leendert; and Caceres, Ramon: Trusted Virtual Domains: Toward secure distributed services. In Proceedings of the 1st IEEE Workshop on Hot Topics in System Dependability (Hot- Dep 05), June [HASK08] Sirrix AG: High-Assurance Security Kernel Protection Profile (EAL5), according to the Common Criteria v3.1 R2, 2007, certified by German Federal Office for Information Security (BSI), [Penn10] Penn, Jonathan: Security and the cloud: Looking at the opportunity beyond the obstacle, Forrester Research, October [Soft11] Software-Cluster, Software-Cluster Koordinierungsstelle, c/o CASED - TU Darmstadt, 2011, [TCG11] Trusted Computing Group, [TClo11] Trustworthy Clouds (TClouds) - Privacy and Resilience for Internet-scale Critical Infrastructure, coordinated by Technikon Forschungs- und Planungsgesellschaft mbh, 2011, tclouds-project.eu/ [TPM11] Trusted Computing Group (TCG), TPM Main Specification, Version 1.2, Revision 116, March 2011.