Over the last decade, container technology has fundamentally changed the landscape of commercial cloud computing services. In contrast to traditional VM technologies, containers theoretically provide the same process isolation guarantees with less overhead and additionally introduce finer grained options for resource allocation. Cloud providers have widely adopted container based architectures as the standard for multi-tenant hosting services and rely on underlying security guarantees to ensure that adversarial workloads cannot disrupt the activities of coresident containers on a given host. Unfortunately, recent work has shown that the isolation guarantees provided by containers are not absolute. Due to inconsistencies in the way cgroups have been added to the Linux kernel, there exist vulnerabilities that allow containerized processes to generate "out of band" workloads and negatively impact the performance of the entire host without being appropriately charged. Because of the relative complexity of the kernel, discovering these vulnerabilities through traditional static analysis tools may be very challenging. In this work, we present TORPEDO, a set of modifications to the SYZKALLER fuzzing framework that creates containerized workloads and searches for sequences of system calls that break process isolation boundaries. TORPEDO combines traditional code coverage feedback with resource utilization measurements to motivate the generation of "adversarial" programs based on user-defined criteria. Experiments conducted on the default docker runtime runC as well as the virtualized runtime gVisor independently reconfirm several known vulnerabilities and discover interesting new results and bugs, giving us a promising framework to conduct more research. / Master of Science / Over the last decade, container technology has fundamentally changed the landscape of commercial cloud computing services. By abstracting away many of the system details required to deploy software, developers can rapidly prototype, deploy, and take advantage of massive distributed frameworks when deploying new software products. These paradigms are supported with corresponding business models offered by cloud providers, who allocate space on powerful physical hardware among many potentially competing services. Unfortunately, recent work has shown that the isolation guarantees provided by containers are not absolute. Due to inconsistencies in the way containers have been implemented by the Linux kernel, there exist vulnerabilities that allow containerized programs to generate "out of band" workloads and negatively impact the performance of other containers. In general, these vulnerabilities are difficult to identify, but can be very severe. In this work, we present TORPEDO, a set of modifications to the SYZKALLER fuzzing framework that creates containerized workloads and searches for programs that negatively impact other containers. TORPEDO uses a novel technique that combines resource monitoring with code coverage approximations, and initial testing on common container software has revealed new interesting vulnerabilities and bugs.
| Identifer | oai:union.ndltd.org:VTETD/oai:vtechworks.lib.vt.edu:10919/104159 |
| Date | 13 July 2021 |
| Creators | McDonough, Kenton Robert |
| Contributors | Computer Science, Wang, Haining, Back, Godmar V., Yao, Danfeng (Daphne) |
| Publisher | Virginia Tech |
| Source Sets | Virginia Tech Theses and Dissertation |
| Detected Language | English |
| Type | Thesis |
| Format | ETD, application/pdf |
| Rights | In Copyright, http://rightsstatements.org/vocab/InC/1.0/ |
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