Biblio
In monolithic operating system (OS), any error of system software can be exploit to destroy the whole system. The situation becomes much more severe in cloud environment, when the kernel and the hypervisor share the same address space. The security of guest Virtual Machines (VMs), both sensitive data and vital code, can no longer be guaranteed, once the hypervisor is compromised. Therefore, it is essential to deploy some security approaches to secure VMs, regardless of the hypervisor is safe or not. Some approaches propose microhypervisor reducing attack surface, or a new software requiring a higher privilege level than hypervisor. In this paper, we propose a novel approach, named HyperPS, which separates the fundamental and crucial privilege into a new trusted environment in order to monitor hypervisor. A pivotal condition for HyperPS is that hypervisor must not be allowed to manipulate any security-sensitive system resources, such as page tables, system control registers, interaction between VM and hypervisor as well as VM memory mapping. Besides, HyperPS proposes a trusted environment which does not rely on any higher privilege than the hypervisor. We have implemented a prototype for KVM hypervisor on x86 platform with multiple VMs running Linux. KVM with HyperPS can be applied to current commercial cloud computing industry with portability. The security analysis shows that this approach can provide effective monitoring against attacks, and the performance evaluation confirms the efficiency of HyperPS.
Security of VMs is now becoming a hot topic due to their outsourcing in cloud computing paradigm. All VMs present on the network are connected to each other, making exploited VMs danger to other VMs. and threats to organization. Rejuvenation of virtualization brought the emergence of hyper-visor based security services like VMI (Virtual machine introspection). As there is a greater chance for any intrusion detection system running on the same system, of being dis-abled by the malware or attacker. Monitoring of VMs using VMI, is one of the most researched and accepted technique, that is used to ensure computer systems security mostly in the paradigm of cloud computing. This thesis presents a work that is to integrate LibVMI with Volatility on a KVM, a Linux based hypervisor, to introspect memory of VMs. Both of these tools are used to monitor the state of live VMs. VMI capability of monitoring VMs is combined with the malware analysis and virtual honeypots to achieve the objective of this project. A testing environment is deployed, where a network of VMs is used to be introspected using Volatility plug-ins. Time execution of each plug-in executed on live VMs is calculated to observe the performance of Volatility plug-ins. All these VMs are deployed as Virtual Honeypots having honey-pots configured on them, which is used as a detection mechanism to trigger alerts when some malware attack the VMs. Using STIX (Structure Threat Information Expression), extracted IOCs are converted into the understandable, flexible, structured and shareable format.
Network Function Virtualization (NFV) is an implementation of cloud computing that leverages virtualization technology to provide on-demand network functions such as firewalls, domain name servers, etc., as software services. One of the methods that help us understand the design and implementation process of such a new system in an abstract way is architectural modeling. Architectural modeling can be presented through UML diagrams to show the interaction between different components and its stakeholders. Also, it can be used to analyze the security threats and the possible countermeasures to mitigate the threats. In this paper, we show some of the possible threats that may jeopardize the security of NFV. We use misuse patterns to analyze misuses based on privilege escalation and VM escape threats. The misuse patterns are part of an ongoing catalog, which is the first step toward building a security reference architecture for NFV.
Monitoring kernel object modification of virtual machine is widely used by virtual-machine-introspection-based security monitors to protect virtual machines in cloud computing, such as monitoring dentry objects to intercept file operations, etc. However, most of the current virtual machine monitors, such as KVM and Xen, only support page-level monitoring, because the Intel EPT technology can only monitor page privilege. If the out-of-virtual-machine security tools want to monitor some kernel objects, they need to intercept the operation of the whole memory page. Since there are some other objects stored in the monitored pages, the modification of them will also trigger the monitor. Therefore, page-level memory monitor usually introduces overhead to related kernel services of the target virtual machine. In this paper, we propose a low-overhead kernel object monitoring approach to reduce the overhead caused by page-level monitor. The core idea is to migrate the target kernel objects to a protected memory area and then to monitor the corresponding new memory pages. Since the new pages only contain the kernel objects to be monitored, other kernel objects will not trigger our monitor. Therefore, our monitor will not introduce runtime overhead to the related kernel service. The experimental results show that our system can monitor target kernel objects effectively only with very low overhead.
With the ever so growing boundaries for security in the cloud, it is necessary to develop ways to prevent from total cloud server failure. In this paper, we try to design a Game Strategy Block that sets up rules for security based on a tower defence game to secure the hypervisor from potential threats. We also try to define a utility function named the Virtual Machine Vitality Measure (VMVM) that could enlighten on the status of the virtual machines on the virtual environment.
Cloud Computing as of large is evolving at a faster pace with an ever changing set of cloud services. The amenities in the cloud are all enabled with respect to the public cloud services in their own enormous domain aspects commercially, which tend to be more insecure. These cloud services should be thus protected and secured which is very vital to the cloud infrastructures. Therefore, in this research work, we have identified security features with a self-heal approach that could be rendered on the infrastructure as a service (IaaS) in a private cloud environment. We have investigated the attack model from the virtual machine snapshots and have analyzed based on the supervised machine learning techniques. The virtual machines memory snapshots API call sequences are considered as input for the supervised and unsupervised machine learning algorithms to classify the attacked and the un-attacked virtual machine memory snapshots. The obtained set of the attacked virtual machine memory snapshots are given as input to the self-heal algorithm which is enabled to retrieve back the functionality of the virtual machines. Our method of detecting the malware attains about 93% of accuracy with respect to the virtual machine snapshots.
Network virtualization is a fundamental technology for datacenters and upcoming wireless communications (e.g., 5G). It takes advantage of software-defined networking (SDN) that provides efficient network management by converting networking fabrics into SDN-capable devices. Moreover, white-box switches, which provide flexible and fast packet processing, are broadly deployed in commercial datacenters. A white-box switch requires a specific and restricted packet processing pipeline; however, to date, there has been no SDN-based network hypervisor that can support the pipeline of white-box switches. Therefore, in this paper, we propose WhiteVisor: a network hypervisor which can support the physical network composed of white-box switches. WhiteVisor converts a flow rule from the virtual network into a packet processing pipeline compatible with the white-box switch. We implement the prototype herein and show its feasibility and effectiveness with pipeline conversion and overhead.
Distributed denial of service (DDoS) attacks is a serious cyberattack that exhausts target machine's processing capacity by sending a huge number of packets from hijacked machines. To minimize resource consumption caused by DDoS attacks, filtering attack packets at source machines is the best approach. Although many studies have explored the detection of DDoS attacks, few studies have proposed DDoS attack prevention schemes that work at source machines. We propose a reliable, lightweight, transparent, and flexible DDoS attack prevention scheme that works at source machines. In this scheme, we employ a hypervisor with a packet filtering mechanism on each managed machine to allow the administrator to easily and reliably suppress packet transmissions. To make the proposed scheme lightweight and transparent, we exploit a thin hypervisor that allows pass-through access to hardware (except for network devices) from the operating system, thereby reducing virtualization overhead and avoiding compromising user experience. To make the proposed scheme flexible, we exploit a configurable packet filtering mechanism with a guaranteed safe code execution mechanism that allows the administrator to provide a filtering policy as executable code. In this study, we implemented the proposed scheme using BitVisor and the Berkeley Packet Filter. Experimental results show that the proposed scheme can suppress arbitrary packet transmissions with negligible latency and throughput overhead compared to a bare metal system without filtering mechanisms.
The diagnosis of performance issues in cloud environments is a challenging problem, due to the different levels of virtualization, the diversity of applications and their interactions on the same physical host. Moreover, because of privacy, security, ease of deployment and execution overhead, an agent-less method, which limits its data collection to the physical host level, is often the only acceptable solution. In this paper, a precise host-based method, to recover wait state for the processes inside a given Virtual Machine (VM), is proposed. The virtual Process State Detection (vPSD) algorithm computes the state of processes through host kernel tracing. The state of a virtual Process (vProcess) is displayed in an interactive trace viewer (Trace Compass) for further inspection. Our proposed VM trace analysis algorithm has been open-sourced for further enhancements and for the benefit of other developers. Experimental evaluations were conducted using a mix of workload types (CPU, Disk, and Network), with different applications like Hadoop, MySQL, and Apache. vPSD, being based on host hypervisor tracing, brings a lower overhead (around 0.03%) as compared to other approaches.
Data privacy and security is a leading concern for providers and customers of cloud computing, where Virtual Machines (VMs) can co-reside within the same underlying physical machine. Side channel attacks within multi-tenant virtualized cloud environments are an established problem, where attackers are able to monitor and exfiltrate data from co-resident VMs. Virtualization services have attempted to mitigate such attacks by preventing VM-to-VM interference on shared hardware by providing logical resource isolation between co-located VMs via an internal virtual network. However, such approaches are also insecure, with attackers capable of performing network channel attacks which bypass mitigation strategies using vectors such as ARP Spoofing, TCP/IP steganography, and DNS poisoning. In this paper we identify a new vulnerability within the internal cloud virtual network, showing that through a combination of TAP impersonation and mirroring, a malicious VM can successfully redirect and monitor network traffic of VMs co-located within the same physical machine. We demonstrate the feasibility of this attack in a prominent cloud platform - OpenStack - under various security requirements and system conditions, and propose countermeasures for mitigation.
ARM devices (mobile phone, IoT devices) are getting more popular in our daily life due to the low power consumption and cost. These devices carry a huge number of user's private information, which attracts attackers' attention and increase the security risk. The operating systems (e.g., Android, Linux) works out many memory data protection strategies on user's private information. However, the monolithic OS may contain security vulnerabilities that are exploited by the attacker to get root or even kernel privilege. Once the kernel privilege is obtained by the attacker, all data protection strategies will be gone and user's private information can be taken away. In this paper, we propose a hardened memory data protection framework called H-Securebox to defeat kernel-level memory data stolen attacks. H-Securebox leverages ARM hardware virtualization technique to protect the data on the memory with hypervisor privilege. We designed three types H-Securebox for programing developers to use. Although the attacker may have kernel privilege, she can not touch private data inside H-Securebox, since hypervisor privilege is higher than kernel privilege. With the implementation of H-Securebox system assisting by a tiny hypervisor on Raspberry Pi2 development board, we measure the performance overhead of our system and do the security evaluations. The results positively show that the overhead is negligible and the malicious application with root or kernel privilege can not access the private data protected by our system.
This is very true for the Windows operating system (OS) used by government and private organizations. With Windows, the closed source nature of the operating system has unfortunately meant that hidden security issues are discovered very late and the fixes are not found in real time. There needs to be a reexamination of current static methods of malware detection. This paper presents an integrated system for automated and real-time monitoring and prediction of rootkit and malware threats for the Windows OS. We propose to host the target Windows machines on the widely used Xen hypervisor, and collect process behavior using virtual memory introspection (VMI). The collected data will be analyzed using state of the art machine learning techniques to quickly isolate malicious process behavior and alert system administrators about potential cyber breaches. This research has two focus areas: identifying memory data structures and developing prediction tools to detect malware. The first part of research focuses on identifying memory data structures affected by malware. This includes extracting the kernel data structures with VMI that are frequently targeted by rootkits/malware. The second part of the research will involve development of a prediction tool using machine learning techniques.
With the extensive application of cloud computing technology developing, security is of paramount importance in Cloud Computing. In the cloud computing environment, surveys have been provided on several intrusion detection techniques for detecting intrusions. We will summarize some literature surveys of various attack taxonomy, which might cause various threats in cloud environment. Such as attacks in virtual machines, attacks on virtual machine monitor, and attacks in tenant network. Besides, we review massive existing solutions proposed in the literature, such as misuse detection techniques, behavior analysis of network traffic, behavior analysis of programs, virtual machine introspection (VMI) techniques, etc. In addition, we have summarized some innovations in the field of cloud security, such as CloudVMI, data mining techniques, artificial intelligence, and block chain technology, etc. At the same time, our team designed and implemented the prototype system of CloudI (Cloud Introspection). CloudI has characteristics of high security, high performance, high expandability and multiple functions.
Live migration is the process used in virtualization environment of datacenters in order to take the benefit of zero downtime during system maintenance. But during migrating live virtual machines along with system files and storage data, network traffic gets increases across network bandwidth and delays in migration time. There is need to reduce the migration time in order to maintain the system performance by analyzing and optimizing the storage overheads which mainly creates due to unnecessary duplicated data transferred during live migration. So there is need of such storage device which will keep the duplicated data residing in both the source as well as target physical host i.e. NAS. The proposed hash map based algorithm maps all I/O operations in order to track the duplicated data by assigning hash value to both NAS and RAM data. Only the unique data then will be sent data to the target host without affecting service level agreement (SLA), without affecting VM migration time, application downtime, SLA violations, VM pre-migration and downtime post migration overheads during pre and post migration of virtual machines.
Virtualization based memory isolation has been widely used as a security primitive in many security systems. This paper firstly provides an in-depth analysis of its effectiveness in the multicore setting, a first in the literature. Our study reveals that memory isolation by itself is inadequate for security. Due to the fundamental design choices in hardware, it faces several challenging issues including page table maintenance, address mapping validation and thread identification. As demonstrated by our attacks implemented on XMHF and BitVisor, these issues undermine the security of memory isolation. Next, we propose a new isolation approach that is immune to the aforementioned problems. In our design, the hypervisor constructs a fully isolated micro computing environment (FIMCE) that exposes a minimal attack surface to an untrusted OS on a multicore platform. By virtue of its architectural niche, FIMCE offers stronger assurance and greater versatility than memory isolation. We have built a prototype of FIMCE and measured its performance. To show the benefits of using FIMCE as a building block, we have also implemented several practical applications which cannot be securely realized by using memory isolation alone.
Numerous event-based probing methods exist for cloud computing environments allowing a hypervisor to gain insight into guest activities. Such event-based probing has been shown to be useful for detecting attacks, system hangs through watchdogs, and for inserting exploit detectors before a system can be patched, among others. Here, we illustrate how to use such probing for trustworthy logging and highlight some of the challenges that existing event-based probing mechanisms do not address. Challenges include ensuring a probe inserted at given address is trustworthy despite the lack of attestation available for probes that have been inserted dynamically. We show how probes can be inserted to ensure proper logging of every invocation of a probed instruction. When combined with attested boot of the hypervisor and guest machines, we can ensure the output stream of monitored events is trustworthy. Using these techniques we build a trustworthy log of certain guest-system-call events. The log powers a cloud-tuned Intrusion Detection System (IDS). New event types are identified that must be added to existing probing systems to ensure attempts to circumvent probes within the guest appear in the log. We highlight the overhead penalties paid by guests to increase guarantees of log completeness when faced with attacks on the guest kernel. Promising results (less that 10% for guests) are shown when a guest relaxes the trade-off between log completeness and overhead. Our demonstrative IDS detects common attack scenarios with simple policies built using our guest behavior recording system.
Just as cloud customers have different performance requirements, they also have different security requirements for their computations in the cloud. Researchers have suggested a "security on demand" service model for cloud computing, where secure computing environment are dynamically provisioned to cloud customers according to their specific security needs. The availability of secure computing platforms is a necessary but not a sufficient solution to convince cloud customers to move their sensitive data and code to the cloud. Cloud customers need further assurance to convince them that the security measures are indeed deployed, and are working correctly. In this paper, we present Policy-Customized Trusted Cloud Service architecture with a new remote attestation scheme and a virtual machine migration protocol, where cloud customer can custom security policy of computing environment and validate whether the current computing environment meets the security policy in the whole life cycle of the virtual machine. To prove the availability of proposed architecture, we realize a prototype that support customer-customized security policy and a VM migration protocol that support customer-customized migration policy and validation based on open source Xen Hypervisor.
Denial of service (DOS) attacks are a serious threat to network security. These attacks are often sourced from virtual machines in the cloud, rather than from the attacker's own machine, to achieve anonymity and higher network bandwidth. Past research focused on analyzing traffic on the destination (victim's) side with predefined thresholds. These approaches have significant disadvantages. They are only passive defenses after the attack, they cannot use the outbound statistical features of attacks, and it is hard to trace back to the attacker with these approaches. In this paper, we propose a DOS attack detection system on the source side in the cloud, based on machine learning techniques. This system leverages statistical information from both the cloud server's hypervisor and the virtual machines, to prevent network packages from being sent out to the outside network. We evaluate nine machine learning algorithms and carefully compare their performance. Our experimental results show that more than 99.7% of four kinds of DOS attacks are successfully detected. Our approach does not degrade performance and can be easily extended to broader DOS attacks.
OpenFlow has recently emerged as a powerful paradigm to help build dynamic, adaptive and agile networks. By decoupling control plane from data plane, OpenFlow allows network operators to program a centralized intelligence, OpenFlow controller, to manage network-wide traffic flows to meet the changing needs. However, from the security's point of view, a buggy or even malicious controller could compromise the control logic, and then the entire network. Even worse, the recent attack Stuxnet on industrial control systems also indicates the similar, severe threat to OpenFlow controllers from the commercial operating systems they are running on. In this paper, we comprehensively studied the attack vectors against the OpenFlow critical component, controller, and proposed a cross layer diversity approach that enables OpenFlow controllers to detect attacks, corruptions, failures, and then automatically continue correct execution. Case studies demonstrate that our approach can protect OpenFlow controllers from threats coming from compromised operating systems and themselves.
In previous work, we proposed a solution to facilitate access to computer science related courses and learning materials using cloud computing and mobile technologies. The solution was positively evaluated by the participants, but most of them indicated that it lacks support for laboratory activities. As it is well known that many of computer science subjects (e.g. Computer Networks, Information Security, Systems Administration, etc.) require a suitable and flexible environment where students can access a set of computers and network devices to successfully complete their hands-on activities. To achieve this criteria, we created a cloud-based virtual laboratory based on OpenStack cloud platform to facilitate access to virtual machine both locally and remotely. Cloud-based virtual labs bring a lot of advantages, such as increased manageability, scalability, high availability and flexibility, to name a few. This arrangement has been tested in a case-study exercise with a group of students as part of Computer Networks and System Administration courses at Kabul Polytechnic University in Afghanistan. To measure success, we introduced a level test to be completed by participants prior and after the experiment. As a result, the learners achieved an average of 17.1 % higher scores in the post level test after completing the practical exercises. Lastly, we distributed a questionnaire after the experiment and students provided positive feedback on the effectiveness and usefulness of the proposed solution.
The cloud has become an established and widespread paradigm. This success is due to the gain of flexibility and savings provided by this technology. However, the main obstacle to full cloud adoption is security. The cloud, as many other systems taking advantage of the Internet, is also facing threats that compromise data confidentiality and availability. In addition, new cloud-specific attacks have emerged and current intrusion detection and prevention mechanisms are not enough to protect the complex infrastructure of the cloud from these vulnerabilities. Furthermore, one of the promises of the cloud is the Quality of Service (QoS) by continuous delivery, which must be ensured even in case of intrusion. This work presents an overview of the main cloud vulnerabilities, along with the solutions proposed in the context of the H2020 CLARUS project in terms of monitoring techniques for intrusion detection and prevention, including attack-tolerance mechanisms.
Hypervisors are the main components for managing virtual machines on cloud computing systems. Thus, the security of hypervisors is very crucial as the whole system could be compromised when just one vulnerability is exploited. In this paper, we assess the vulnerabilities of widely used hypervisors including VMware ESXi, Citrix XenServer and KVM using the NIST 800-115 security testing framework. We perform real experiments to assess the vulnerabilities of those hypervisors using security testing tools. The results are evaluated using weakness information from CWE, and using vulnerability information from CVE. We also compute the severity scores using CVSS information. All vulnerabilities found of three hypervisors will be compared in terms of weaknesses, severity scores and impact. The experimental results showed that ESXi and XenServer have common weaknesses and vulnerabilities whereas KVM has fewer vulnerabilities. In addition, we discover a new vulnerability called HTTP response splitting on ESXi Web interface.