Overview
Virtualization is essential for mobility and resilience, but hypervisor foundations need strong controls to balance functionality and security. The infrastructure supporting cloud computing has shifted to software-defined virtualization, allowing flexible resource allocation through guest virtual machines isolated from real servers. This improves utilization, availability, and scalability. However, the hypervisor layer coordinating hardware sharing creates crucial new attack surfaces that must be mitigated. Whether Type-1 bare metal hypervisors running directly on hosts or Type-2 hosted variations contained in base operating systems, these machine interpreters have the most privileges for managing VMs on top. This control concentration is also risky. Virtualization promotes economies of scale, but concurrent VMs multiply vulnerabilities that could be exploited to lateral through networks. Since usage spread before security maturity, hypervisor code exposures have increased. Threats include guest VM escapes, hacked management consoles, insider threats, and hypervisor hooking attempts to increase privileges or steal data. Misconfigurations increase dangers without controls (Aalam et al., 2021).
Types of Hypervisors
Type 1 hypervisor installs directly on server hardware without an operating system. The Type 1 hypervisor manages resource allocation and partitioning as its own operating system. Since guest virtual machines don’t run through a host OS, type 1 hypervisors function nearly natively. They optimize security and isolation amongst virtual computers sharing hardware. Compared to hosted architectural solutions, Type 1 hypervisors offer less flexibility and heterogeneity (Aalam et al., 2021). On the other hand, hosted type 2 hypervisors run on standard operating systems. The hypervisor software layer above the host operating system coordinates guest-hardware calls. They are lighter and better for client-based installations, testing, and running fewer guest VMs. Since resource calls go through the host OS, performance is slightly worse than bare metal (Chakkaravarthy et al., 2019).
Hypervisor Security
Type hypervisors are considered more secure than hosted Type 2 options. They do this because their tiny specialized architecture interacts directly with the hardware layer rather than going through a host OS. Type 1 hypervisors isolate virtual machines by taking over server hardware and partitioning resources with their native kernels. Compared to Type 2 technologies, bare-metal limits hardware access better, limiting attack surface area. Any resource manipulation must pass through the hypervisor security gateway, not the host OS (Chakkaravarthy et al., 2019). Furthermore, type 1 hypervisors are on the lowest layer, so their integrity aligns with the hardware root of trust primitives for security attestations. Due to the intervening host OS, hosted Type 2 architectures cannot guarantee a secure boot. However, bare-metal hypervisors’ cleaner and more streamlined architecture reduce multi-tenant security risks, making Type 1 solutions ideal for isolation-centric workloads. The firm can rationally consolidate applications requiring trustworthy partitioning onto shared infrastructure using their significant security advantages (Sethuraman & Khan, 2023).
Threats Discussed
Modification in Hypervisor
This is where attackers directly edit hypervisor code to compromise security. Subverting hypervisors’ control layers grants root access to the entire server stack, making them enticing targets. Backdoors or hidden privileged paths could be injected using hypervisor vulnerabilities. These threats include virtual machine-based rootkits, and stealthy malware that brokers guest access for malevolent purposes in hypervisor resident memory. Such rootkits activate randomly, operate without host OS visibility, and are difficult to detect and delete (Chakkaravarthy et al., 2019).
Guest-to-Guest Attack
This refers to an infected VM using the hypervisor vector to attack peer guest VMs in multi-tenant virtualized systems. Malicious VMs use shared memory and virtual networks to move laterally through trusted channels not accessible in non-virtualized environments. A hacked VM could leak killer packets over an internal virtual network, crashing or backdooring neighbor VMs. Segregation controls are essential with everything virtualized by the hypervisor (Sethuraman & Khan, 2023).
Data Stealing
Hypervisors significantly increase network-accessible virtual machine data theft attack surfaces. The report warns that rogue insiders or malware with remote network access can steal and copy complete VM image files containing sensitive data. A web application VM exploited by SQL injection could extract key databases with high-value data. Virtualization mobility lets attackers steal entire VM clones without physical access (Aalam et al., 2021).
Hypervisor Intrusion
This refers to full hypervisor compromise, allowing adversaries to manage hardware resources. As with VMBR attacks, the attacker wants to run malicious code as root on the hypervisor. Even a partially exploited hypervisor could intercept infected guest VM instructions to conduct more attacks. Attackers undermine hardware and workload trust by gaining complete control over the virtualization stack. Preventing intrusion requires hardening the hypervisor control layer (Arriaga et al., 2020).
References
Aalam, Z., Kumar, V., & Gour, S. (2021, August). A review paper on hypervisor and virtual machine security. In Journal of Physics: Conference Series (Vol. 1950, No. 1, p. 012027). IOP Publishing. https://wilmu.instructure.com/courses/63654/files/10007040?wrap=1
Arriaga, F., Branco, R., & Lee, B. (2020). Security issues and challenges for virtualization technologies. ACM Computing Surveys (CSUR), 53(2), 1-37. https://dl.acm.org/doi/abs/10.1145/3382190
Chakkaravarthy, S. S., Sangeetha, D., & Vaidehi, V. (2019). A survey on malware analysis and mitigation techniques. Computer Science Review, 32, 1-23. https://www.sciencedirect.com/science/article/pii/S1574013718301114
Sethuraman, S. C., & Khan, M. K. (2023). Container Security: Precaution Levels, Mitigation Strategies, and Research Perspectives. Computers & Security, 103490. https://www.sciencedirect.com/science/article/pii/S0167404823004005
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