Finding the Balance Between Guidance and Independence in Cybersecurity Exercises

Abstract In order to accomplish cyber security tasks, one needs to know how to analyze complex data and when and how to use tools. Many hands-on exercises for cybersecurity courses have been developed to teach these skills. There is a spectrum of ways that these exercises can be taught. On one end of the spectrum are prescriptive exercises, in which students follow step-by-step instructions to run scripted exploits, perform penetration testing, do security audits, etc. On the other end of the spectrum are open-ended exercises and capture-the-flag activities, where little guidance is given on how to proceed. This paper reports on our experience with trying to find a balance between these extremes in the context of one of the suite of cybersecurity exercises that we have developed in the EDURange framework 1 . The particular exercise that we present teaches students about dynamic analysis of binaries using strace. We have found that students are most successful in these exercises when they are given the right amount of prerequisite knowledge and guidance as well as some opportunity to find creative solutions. Our scenarios are specifically designed to develop analysis skills and the security mindset in students and to complement the theoretical aspects of the discipline and develop practical skills

SegSlice: Towards a New Class of Secure Programming Primitives for Trustworthy Platforms

Abstract. The TPM is a fairly passive entity. As a result, it can be difficult to involve the TPM in measurements of software trustworthiness beyond simple load-time hashing of static program code. We suggest an approach to dynamic, runtime measurement of software trustworthiness properties as they relate to code-data owernship relationships. We outline a system, SegSlice, that actively involves the TPM in fine-grained labeling and measurement of code slices and the data that these slices operate on. SegSlice requires no changes to x86 hardware, and it relies on the relatively underused x86 segmentation mechanism to mediate access to data events.

Secure Code Updates for Smart Embedded Devices based on PUFs

Code update is a very useful tool commonly used in low-end embedded devices to improve the existing functionalities or patch discovered bugs or vulnerabilities. If the update protocol itself is not secure, it will only bring new threats to embedded systems. Thus, a secure code update mechanism is required. However, existing solutions either rely on strong security assumptions, or result in considerable storage and computation consumption, which are not practical for resource-constrained embedded devices (e.g., in the context of Internet of Things). In this work, we propose to use intrinsic device characteristics (i.e., Physically Unclonable Functions or PUF) to design a practical and lightweight secure code update scheme. Our scheme can not only ensure the freshness, integrity, confidentiality and authenticity of code update, but also verify that the update is installed correctly on a specific device without any malicious software. Cloned or counterfeit devices can be excluded as the code update is bound to the unpredictable physical properties of underlying hardware. Legitimate devices in an untrustworthy software state can be restored by filling suspect memory with PUF-derived random numbers. After update installation, the initiator of the code update is able to obtain the verifiable software state from device, and the device can maintain a sustainable post-update secure check by enforcing a secure call sequence. To demonstrate the practicality and feasibility, we also implement the proposed scheme on a low-end MCU platform (TI MSP430) by using onboard SRAM and Flash resources

ELFbac: Using the Loader Format for Intent-Level Semantics and Fine-Grained Protection

Adversaries get software to do bad things by rewriting memory and changing control flow. Current approaches to protecting against these attacks leave many exposures; for example, OS-level filesystem protection and OS/architecture support of the userspace/kernelspace distinction fail to protect corrupted userspace code from changing userspace data. In this paper we present a new approach: using the ELF/ABI sections already produced by the standard binary toolchain to define, specify, and enforce fine-grained policy within an application\u27s address space. We experimentally show that enforcement of such policies would stop a large body of current attacks and discuss ways we could extend existing architecture to more efficiently provide such enforcement. Our approach is designed to work with existing ELF executables and the GNU build chain, but it can be extended into the compiler toolchains to support code annotations that take advantage of ELFbac enforcement-while maintaining full compatibility with the existing ELF ABI

A pattern-based development of secure business processes

Iga andmeturbest huvitatud äriettevõte valib iseendale sobilikud turvameetmed, et vältida ootamatuid sündmusi ja õnnetusi. Nende turvameetmete esmane ülesanne on kaitsta selle äriettevõtte ressursse ja varasid. Äriettevõtetes aset leidvad õnnetused (vähemtähtsad või katastroofilised) on enamikel juhtudel oma olemuselt sarnased ning põhjustatud sarnaste turvariskide poolt. Paljudel andmeturbe spetsialistidel on raskusi leidmaks õiget lahendust konkreetsetele probleemidele, kuna eelmiste samalaadsete probleemide lahendused ei ole korrektselt dokumenteeritud. Selles kontekstis on turvalisuse mustrid (Security Patterns) kasulikud, kuna nad esitavad tõestatud lahendusi spetsiifiliste probleemide jaoks. Käesolevas väitekirjas arendasime välja kümme turvariskidele suunatud mustrit (SRP ehk Security Risk-oriented Patterns) ja defineerisime, kuidas kasutada neid mustreid vastumeetmetena turvariskidele äriprotsesside mudelite sees. Oma olemuselt on need mustrid sõltumatud modelleerimiskeelest. Lihtsustamaks nende rakendamist, on mudelid esitatud graafilises vormingus äriprotsesside modelleerimise keeles (BPMN). Me demonstreerime turvariskidele suunatud mustrite (SRP) kasutatavust kahe tööstusettevõtte ärimudeli näite põhjal. Esitame mustrite rakendamise kohta kvantitatiivsed analüüsid ja näitame, kuidas turvariskidele suunatud mustrid (SRP) aitavad demonstreerida andmeturbe nõrku kohti ärimudelites ning pakume välja lahendusi andmeturvalisusega seotud probleemidele. Selle uurimistöö tulemused võivad julgustada andmeturvalisusega tegelevaid analüütikuid jälgima mustritel-põhinevaid lähenemisi oma äriettevõtete kaitsmiseks, et aidata seeläbi kaasa ka infosüsteemide (Information Systems (IS)) kaitsmisele.Every security concerned enterprise selects its own security measures in order to avoid unexpected events and accidents. The main objective of these security measures is to protect the enterprise’s own resources and assets from damage. Most of the time, the accidents or disasters take place in enterprise are similar in nature, and are caused by similar kind of vulnerabilities. However, many security analysts find it difficult to select the right security measure for a particular problem because the previous proven solutions are not properly documented. In this context Security Patterns could be helpful since they present the proven solutions that potentially could be reused in the similar situations. In this thesis, we develop a set of ten Security Risk-oriented Patterns (SRP) and define the way how they could be used to define security countermeasures within the business process models. In principle, patterns are modelling language-independent. Moreover, to ease their application, we represent them in a graphical form using the Business Process Modelling Notation (BPMN) modelling approach. We demonstrate the usability of the Security Risk-oriented Patterns (SRP) by applying them on two industrial business models. We present the quantitative analysis of their application. We show that Security Risk-oriented Patterns (SRP) help to determine security risks in business models and suggest rationale for security solutions. The results of this research could potentially encourage the security analysts to follow pattern-based approach to develop secure business processes, thus, contributing to secure Information Systems (IS)

Autoscopy Jr.: Intrusion Detection for Embedded Control Systems

Securing embedded control systems within the power grid presents a unique challenge: on top of the resource restrictions inherent to these devices, SCADA systems must also accommodate strict timing requirements that are non-negotiable, and their massive scale greatly amplifies costs such as power consumption. These constraints make the conventional approach to host intrusion detection--namely, employing virtualization in some manner--too costly or impractical for embedded control systems within critical infrastructure. Instead, we take an in-kernel approach to system protection, building upon the Autoscopy system developed by Ashwin Ramaswamy that places probes on indirectly-called functions and uses them to monitor its host system for behavior characteristic of control-flow-altering malware, such as rootkits. In this thesis, we attempt to show that such a method would indeed be a viable method of protecting embedded control systems. We first identify several issues with the original prototype, and present a new version of the program (dubbed Autoscopy Jr.) that uses trusted location lists to verify that control is coming from a known, trusted location inside our kernel. Although we encountered additional performance overhead when testing our new design, we developed a kernel profiler that allowed us to identify the probes responsible for this overhead and discard them, leaving us with a final probe list that generated less than 5% overhead on every one of our benchmark tests. Finally, we attempted to run Autoscopy Jr. on two specialized kernels (one with an optimized probing framework, and another with a hardening patch installed), finding that the former did not produce enough performance benefits to preclude using our profiler, and that the latter required a different method of scanning for indirect functions for Autoscopy Jr. to operate. We argue that Autoscopy Jr. is indeed a feasible intrusion detection system for embedded control systems, as it can adapt easily to a variety of system architectures and allows us to intelligently balance security and performance on these critical devices

Attestation in Trusted Computing: Challenges and Potential Solutions

This report examines the state of play in TCG attestation. It asks the question: how practical is the attestation specification and does it meet the needs of designs that propose to take advantage of trusted computing functionality? It is shown that, broadly speaking, both specification and implementation falls short of its stated goals. Application designs expect different semantics. Straightforward application of attestation to a running system does not provide adequate assurance nor does it scale. It is argued that extending the TCG architecture and reworking application designs are the most viable routes to making attestation a practical proposition

Monitoring the health and integrity of Wireless Sensor Networks

Wireless Sensor Networks (WSNs) will play a major role in the Internet of Things collecting the data that will support decision-making and enable the automation of many applications. Nevertheless, the introduction of these devices into our daily life raises serious concerns about their integrity. Therefore, at any given point, one must be able to tell whether or not a node has been compromised. Moreover, it is crucial to understand how the compromise of a particular node or set of nodes may affect the network operation. In this thesis, we present a framework to monitor the health and integrity of WSNs that allows us to detect compromised devices and comprehend how they might impact a network’s performance. We start by investigating the use of attestation to identify malicious nodes and advance the state of the art by exploring limitations of existing mechanisms. Firstly, we tackle effectiveness and scalability by combining attestation with measurements inspection and show that the right combination of both schemes can achieve high accuracy whilst significantly reducing power consumption. Secondly, we propose a novel stochastic software-based attestation approach that relaxes a fundamental and yet overlooked assumption made in the literature significantly reducing time and energy consumption while improving the detection rate of honest devices. Lastly, we propose a mathematical model to represent the health of a WSN according to its abilities to perform its functions. Our model combines the knowledge regarding compromised nodes with additional information that quantifies the importance of each node. In this context, we propose a new centrality measure and analyse how well existing metrics can rank the importance each sensor node has on the network connectivity. We demonstrate that while no measure is invariably better, our proposed metric outperforms the others in the vast majority of cases.Open Acces

Ordered Merkle Tree a Versatile Data-Structure for Security Kernels

Hidden undesired functionality is an unavoidable reality in any complex hardware or software component. Undesired functionality — deliberately introduced Trojan horses or accidentally introduced bugs — in any component of a system can be exploited by attackers to exert control over the system. This poses a serious security risk to systems — especially in the ever growing number of systems based on networks of computers. The approach adopted in this dissertation to secure systems seeks immunity from hidden functionality. Specifcally, if a minimal trusted computing base (TCB) for any system can be identifed, and if we can eliminate hidden functionality in the TCB, all desired assurances regarding the operation of the system can be guaranteed. More specifcally, the desired assurances are guaranteed even if undesired functionality may exist in every component of the system outside the TCB. A broad goal of this dissertation is to characterize the TCB for various systems as a set of functions executed by a trusted security kernel. Some constraints are deliberately imposed on the security kernel functionality to reduce the risk of hidden functionality inside the security kernel. In the security model adopted in this dissertation, any system is seen as an interconnection of subsystems, where each subsystem is associated with a security kernel. The security kernel for a subsystem performs only the bare minimal tasks required to assure the integrity of the tasks performed by the subsystem. Even while the security kernel functionality may be different for each system/subsystem, it is essential to identify reusable components of the functionality that are suitable for a wide range of systems. The contribution of the research is a versatile data-structure — Ordered Merkle Tree (OMT), which can act as the reusable component of various security kernels. The utility of OMT is illustrated by designing security kernels for subsystems participating in, 1) a remote fle storage system, 2) a generic content distribution system, 3) generic look-up servers, 4) mobile ad-hoc networks and 5) the Internet’s routing infrastructure based on the border gateway protocol (BGP)