Fuzzing is a key tool used to reduce bugs in production software. At Google, fuzzing has uncovered tens of thousands of bugs. Fuzzing is also a popular subject of academic research. In 2020 alone, over 120 papers were published on the topic of improving, developing, and evaluating fuzzers and fuzzing techniques. Yet, proper evaluation of fuzzing techniques remains elusive. The community has struggled to converge on methodology and standard tools for fuzzer evaluation.

The popularity of hardware-based Trusted Execution Environments (TEEs) has recently skyrocketed with the introduction of Intel's Software Guard Extensions (SGX). In SGX, the user process is protected from supervisor software, such as the operating system, through an isolated execution environment called an enclave. Despite the isolation guarantees provided by TEEs, numerous microarchitectural side channel attacks have been demonstrated that bypass their defense mechanisms. But, not all hope is lost for defenders: many modern fine-grain, high-resolution side channels---e.g., execution unit port contention---introduce large amounts of noise, complicating the adversary's task to reliably extract secrets.

Although clouds have strong virtual memory isolation guarantees, cache attacks stemming from shared caches have proved to be a large security problem. However, despite the past effectiveness of cache attacks, their viability has recently been called into question on modern systems, due to trends in cache hierarchy design moving away from inclusive cache hierarchies. In this paper, we reverse engineer the structure of the directory in a sliced, non-inclusive cache hierarchy, and prove that the directory can be used to bootstrap conflict-based cache attacks on the last-level cache. We design the first cross-core Prime+Probe attack on non-inclusive caches. This attack works with minimal assumptions: the adversary does not need to share any virtual memory with the victim, nor run on the same processor core. We also show the first high-bandwidth Evict+Reload attack on the same hardware. We demonstrate both attacks by extracting key bits during RSA operations in GnuPG on a state-of-the-art non-inclusive Intel Skylake-X server.

Despite the isolation mechanisms that are available to cloud service providers, like virtual machines and containers, the problem of side-channel vulnerabilities due to shared caches and multicore processors remains a threat. We present a hardware-software mechanism that improves the isolation of cloud processes in the presence of shared caches on multicore chips. Our technique can enable cache-side-channel free computing for Linux-based containers and virtual machines by com-bining the Intel CAT architecture that enables cache partitioning with novel scheduling techniques and state cleansing mechanisms. We evaluate our system using a CPU-bound workload and demonstrate cache-side-channel-free computation that is correct by construction. Our system allows Simultaneous Multithreading to remain enabled and does not require application level changes.

The increasing relevance of information assurance in cloud computing has forced governments and stakeholders to turn their attention to Information Technology (IT) security certifications and standards. The introduction of new frameworks such as FedRAMP in the US and C5 in Germany is aimed to raise the level of protection against threats and vulnerabilities unique to cloud computing. However, our in-depth and systematic analyses reveals that these new standards do not bring a radical change in the realm of certifications. Results also shows that the newly developed standards share much of their basis with older, more consolidated standards such as the ISO/IEC 27001 and hence the need for determining the added value. In this study, we provide an overview of ISO/IEC 27001, C5, and FedRAMP while examining their completeness and adequacy in addressing current threats to cloud assurance. We question the level of protection they offer by comparing these three certifications alongside each other. We identify weaknesses in the three frameworks and highlight necessary improvements to meet the security requirements indispensable in relation to the current threat landscape.

To demonstrate compliance with privacy and security principles, information technology (IT) service providers often rely on security standards and certifications. However, the appearance of new service models such as cloud computing has brought new threats to information assurance, weakening the protection that existing standards can provide. In this study, we analyze four highly regarded IT security standards used to assess, improve, and demonstrate information systems assurance and cloud security. ISO/IEC 27001, SOC 2, C5, and FedRAMP are standards adopted worldwide and constantly updated and improved since the first release of ISO in 2005. We examine their adequacy in addressing current threats to cloud security, and provide an overview of the evolution over the years of their ability to cope with threats and vulnerabilities. By comparing the standards alongside each other, we investigate their complementarity, their redundancies, and the level of protection they offer to information stored in cloud systems. We unveil vulnerabilities left unaddressed in the four frameworks, thus questioning the necessity of multiple standards to assess cloud assurance. We suggest necessary improvements to meet the security requirements made indispensable by the current threat landscape.

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.

This paper extends the concepts behind cloud services to offer hypervisor-based reliability and security monitors for cloud virtual machines. Cloud VMs can be heterogeneous and as such guest OS parameters needed for monitoring can vary across different VMs and must be obtained in some way. Past work involves running code inside the VM, which is unacceptable for a cloud environment. We solve this problem by recognizing that there are common OS design patterns that can be used to infer monitoring parameters from the guest OS. We extract information about the cloud user's guest OS with the user's existing VM image and knowledge of OS design patterns as the only inputs to analysis. To demonstrate the range of monitoring functionality possible with this technique, we implemented four sample monitors: a guest OS process tracer, an OS hang detector, a return-to-user attack detector, and a process-based keylogger detector.

Virtual machine introspection (VMI) has grown into a number of novel security measures in recent years. Virtualized environments provide isolation, which gives way to better security. This paper presents an extension, WinWizard, of LibVMI that creates a VMI-based intrusion detection system (IDS) with emphasis on memory introspection. WinWizard is able to detect rootkits that attempts to hide processes from the administrator. Rootkits are able to subvert traditional virus scanning services because they are able to run at the kernel level. Rootkit detection becomes difficult because if the operating system has been subverted, especially at the kernel level, then it is difficult to find unauthorized changes to itself or its components. Most anti-viruses and other rootkit detectors that work on infected systems are usually only effective against rookits that have a defect in their hiding techniques. Rootkit detection through VMI is one way to effectively detect rookits. VMI detection tools will also be useful in industry. Industry is beginning to advance in its usage of cloud based workspaces. Examples of companies include Amazons Workspaces and Citrix XenDesktop. They offer remote desktops for small and medium sized businesses. These workspaces offer a fully managed cloud-based desktop experience where users can access their work resources from a variety of devices. Many universities and small businesses use services like these to reduce the number of IT staff and ease administration of a large number of desktops. As this field becomes more accessible, rootkits are going to drastically affect the performance and security of not only one users desktop, but on entire cloud infrastructures. The main way to detect a rootkit inside of these workspaces would be through virtual machine introspection. WinWinzard has demonstrated to be successful in detecting these types of rootkits, while causing little additional overhead to other virtual machines being hosted on the same hypervisor.