A framework for designing cloud forensic‑enabled services (CFeS)

Cloud computing is used by consumers to access cloud services. Malicious actors exploit vulnerabilities of cloud services to attack consumers. The link between these two assumptions is the cloud service. Although cloud forensics assists in the direction of investigating and solving cloud-based cyber-crimes, in many cases the design and implementation of cloud services falls back. Software designers and engineers should focus their attention on the design and implementation of cloud services that can be investigated in a forensic sound manner. This paper presents a methodology that aims on assisting designers to design cloud forensic-enabled services. The methodology supports the design of cloud services by implementing a number of steps to make the services cloud forensic-enabled. It consists of a set of cloud forensic constraints, a modelling language expressed through a conceptual model and a process based on the concepts identified and presented in the model. The main advantage of the proposed methodology is the correlation of cloud services’ characteristics with the cloud investigation while providing software engineers the ability to design and implement cloud forensic-enabled services via the use of a set of predefined forensic related task

Decentralised and Collaborative Auditing of Workflows

Workflows involve actions and decision making at the level of each participant. Trusted generation, collection and storage of evidence is fundamental for these systems to assert accountability in case of disputes. Ensuring the security of audit systems requires reliable protection of evidence in order to cope with its confidentiality, its integrity at generation and storage phases, as well as its availability. Collusion with an audit authority is a threat that can affect all these security aspects, and there is room for improvement in existent approaches that target this problem. This work presents an approach for workflow auditing which targets security challenges of collusion-related threats, covers different trust and confidentiality requirements, and offers flexible levels of scrutiny for reported events. It relies on participants verifying each other's reported audit data, and introduces a secure mechanism to share encrypted audit trails with participants while protecting their confidentiality. We discuss the adequacy of our audit approach to produce reliable evidence despite possible collusion to destroy, tamper with, or hide evidence

Trustworthy And Efficient Digital Forensics In The Cloud

The rise of cloud computing has changed the way of using computing services and resources. However, the black-box nature of clouds and the multi-tenant cloud models have brought new security risks, especially in terms of digital forensics. Current cloud computing architectures often lack support for digital forensic investigations since many of the assumptions that are valid for traditional computing environment are invalid in clouds. Current digital forensics tools and procedures rely on the physical access to the evidence. In clouds, computing and storage resources are no longer local and these resources are also shared between multiple cloud users. Hence, even with a subpoena, forensics investigators cannot confiscate a suspect’s computer and get access to the digital evidence that reside in the cloud. Data in the virtual machines (VM) are not also accessible after terminating the VMs. Hence, investigators need to depend on the Cloud Service Providers (CSP) to acquire various important evidence, such as activity logs of VMs, files stored in clouds, VM images, etc. Unfortunately, current cloud architectures do not guarantee that a CSP is providing valid evidence to investigators. A CSP in its entirety or a malicious employee of the CSP can collude with an adversary or a dishonest investigator to tamper with the evidence. Moreover, forensics investigators can also alter the evidence before presenting to a court. Hence, for a reliable digital forensics investigation in clouds, we need to ensure the integrity of the evidence and the privacy of users in the multi-tenant cloud environment. In this dissertation, we explore techniques for ensuring the trustworthiness of various types of evidence in a strong adversarial scenario. We show that, without incurring high performance overheads, we can preserve and provide required evidence for digital forensics investigations involving clouds, while protecting the privacy and integrity of the evidence. We propose an Open Cloud Forensics model (OCF) and adapt this model to design forensics-enabled architectures for Infrastructure-as-a-Service (IaaS) and Storage-as-a-Service (STaaS) clouds. For IaaS clouds, we first focus on the trustworthiness of activity logs of cloud users. We design a logging scheme to securely retrieve, store, and expose these activity logs to forensics investigators. To ensure the trustworthiness of the time associated with the logs, we propose a tamper-evident scheme to prove iii the correctness of the system time of cloud hosts and VMs. To parse and store heterogeneous formats of logs securely in a convenient way, we develop the Forensics Aware Language (FAL) – a domain specific language. Next, we focus on the data possession information for STaaS clouds. In this regard, we first design a proof of past data possession scheme to prove the data possession of a particular user at a given past time. We then develop a secure litigation hold management scheme to provide the assurance of maintaining litigation holds on data stored in the cloud. Next, we investigate secure provenance for clouds and develop an efficient, secure data provenance scheme. We integrate all the proposed schemes with an open source cloud platform – OpenStack, and show the efficiency of the schemes. Finally, we investigate the big data forensics domain and design a cloud-based system to expedite the process of digital forensics investigations involving big data