105 research outputs found

    Ensuring system integrity and security on limited environment systems

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    Cyber security threats have rapidly developed in recent years and should also be considered when building or implementing systems that traditionally have not been connected to networks. More and more these systems are getting networked and controlled remotely, which widens their attack surface and lays them open to cyber threats. This means the systems should be able to detect and block malware threats without letting the controls affect daily operations. File integrity monitoring and protection could be one way to protect systems from emerging threats. The use case for this study is a computer system, that controls medical device. This kind of system does not necessarily have an internet connection and is not connected to a LAN network by default. Ensuring integrity on the system is critical as if the system would be infected by a malware, it could affect to the test results. This thesis studies what are the feasible ways to ensure system integrity on limited environment systems. Firstly these methods and tools are listed through a literature review. All of the tools are studied how they protect the system integrity. The literature review aims to select methods for further testing through a deductive reasoning. After selecting methods for testing, their implementations are installed to the testing environment. The methods are first tested for performance and then their detection and blocking capability is tested against real life threats. Finally, this thesis proposes a method which could be implemented to the presented use case. The proposal at the end is based on the conducted tests

    Autoscopy: Detecting Pattern-Searching Rootkits via Control Flow Tracing

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    Traditional approaches to rootkit detection assume the execution of code at a privilege level below that of the operating system kernel, with the use of virtual machine technologies to enable the detection system itself to be immune from the virus or rootkit code. In this thesis, we approach the problem of rootkit detection from the standpoint of tracing and instrumentation techniques, which work from within the kernel and also modify the kernel\u27s run-time state to detect aberrant control flows. We wish to investigate the role of emerging tracing frameworks (Kprobes, DTrace etc.) in enforcing operating system security without the reliance on a full-blown virtual machine just for the purposes of such policing. We first build a novel rootkit prototype that uses pattern-searching techniques to hijack hooks embedded in dynamically allocated memory, which we present as a showcase of emerging attack techniques. We then build an intrusion detection system-- autoscopy, atop kprobes, that detects anomalous control flow patterns typically exhibited by rootkits within a running kernel. Furthermore, to validate our approach, we show that we were able to successfully detect 15 existing Linux rootkits. We also conduct performance analyses, which show the overhead of our system to range from 2% to 5% on a wide range of standard benchmarks. Thus by leveraging tracing frameworks within operating systems, we show that it is possible to introduce real-world security in devices where performance and resource constraints are tantamount to security considerations

    An Automated Methodology for Validating Web Related Cyber Threat Intelligence by Implementing a Honeyclient

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    Loodud töö panustab küberkaitse valdkonda pakkudes alternatiivse viisi, kuidas hoida ohuteadmus andmebaas uuendatuna. Veebilehti kasutatakse ära viisina toimetada pahatahtlik kood ohvrini. Peale veebilehe klassifitseerimist pahaloomuliseks lisatakse see ohuteadmus andmebaasi kui pahaloomulise indikaatorina. Lõppkokkuvõtteks muutuvad sellised andmebaasid mahukaks ja sisaldavad aegunud kirjeid. Lahendus on automatiseerida aegunud kirjete kontrollimist klient-meepott tarkvaraga ning kogu protsess on täielikult automatiseeritav eesmärgiga hoida kokku aega. Jahtides kontrollitud ja kinnitatud indikaatoreid aitab see vältida valedel alustel küberturbe intsidentide menetlemist.This paper is contributing to the open source cybersecurity community by providing an alternative methodology for analyzing web related cyber threat intelligence. Websites are used commonly as an attack vector to spread malicious content crafted by any malicious party. These websites become threat intelligence which can be stored and collected into corresponding databases. Eventually these cyber threat databases become obsolete and can lead to false positive investigations in cyber incident response. The solution is to keep the threat indicator entries valid by verifying their content and this process can be fully automated to keep the process less time consuming. The proposed technical solution is a low interaction honeyclient regularly tasked to verify the content of the web based threat indicators. Due to the huge amount of database entries, this way most of the web based threat indicators can be automatically validated with less time consumption and they can be kept relevant for monitoring purposes and eventually can lead to avoiding false positives in an incident response processes

    Micro-architectural Threats to Modern Computing Systems

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    With the abundance of cheap computing power and high-speed internet, cloud and mobile computing replaced traditional computers. As computing models evolved, newer CPUs were fitted with additional cores and larger caches to accommodate run multiple processes concurrently. In direct relation to these changes, shared hardware resources emerged and became a source of side-channel leakage. Although side-channel attacks have been known for a long time, these changes made them practical on shared hardware systems. In addition to side-channels, concurrent execution also opened the door to practical quality of service attacks (QoS). The goal of this dissertation is to identify side-channel leakages and architectural bottlenecks on modern computing systems and introduce exploits. To that end, we introduce side-channel attacks on cloud systems to recover sensitive information such as code execution, software identity as well as cryptographic secrets. Moreover, we introduce a hard to detect QoS attack that can cause over 90+\% slowdown. We demonstrate our attack by designing an Android app that causes degradation via memory bus locking. While practical and quite powerful, mounting side-channel attacks is akin to listening on a private conversation in a crowded train station. Significant manual labor is required to de-noise and synchronizes the leakage trace and extract features. With this motivation, we apply machine learning (ML) to automate and scale the data analysis. We show that classical machine learning methods, as well as more complicated convolutional neural networks (CNN), can be trained to extract useful information from side-channel leakage trace. Finally, we propose the DeepCloak framework as a countermeasure against side-channel attacks. We argue that by exploiting adversarial learning (AL), an inherent weakness of ML, as a defensive tool against side-channel attacks, we can cloak side-channel trace of a process. With DeepCloak, we show that it is possible to trick highly accurate (99+\% accuracy) CNN classifiers. Moreover, we investigate defenses against AL to determine if an attacker can protect itself from DeepCloak by applying adversarial re-training and defensive distillation. We show that even in the presence of an intelligent adversary that employs such techniques, DeepCloak still succeeds
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