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Password deposition techniques in operating systems
Pavlík, Martin ; Růčka, Lukáš (referee) ; Hajný, Jan (advisor)
This master thesis deals with ways to store passwords in current operating systems. Specifically, this work focuses on Windows, Linux, BSD and OS X. These systems are examined for ways of hashing passwords and on resistance of resulting hashes against various attacks. First (theoretical) section describes the procedures and algorithms that are needed for user authentication. This part also describes methods of hash storing. At the end of the theoretical part are generally described some possible attacks against hash functions. In second (practical) part is described and tested tools for obtaining hashes of the investigated operating systems. Subsequently practical attacks were conducted against obtained hashes by using appropriate tools. Furthermore there are presented results of the attacks. In the conclusion of the work there is a comparison of tools and methods which were used to obtain plaintext passwords from operating systems.
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Influence of Network Infrastructure on Distributed Password Cracking
Eisner, Michal ; Zobal, Lukáš (referee) ; Hranický, Radek (advisor)
Password cracking is a process used to obtain the cracking key through which we get access to encrypted data. This process normally works on the principle of the repeated try of attempts and their verification by making calculations of cryptographic algorithms. The difficulty of algorithms affects the time spent on solving of the calculations. In spite of various acceleration methods, it is often necessary to distribute the given problem among several nodes which are interconnected via the local network or the internet. The aim of this thesis is to analyze the influence of network infrastructure on the speed, the scalability, and the utilization during different attacks on cryptographical hashes. For these purposes, there was created an automatized experimental environment, which consists of distinctive topologies, scripts, and sets of testing tasks. Based on the results of the analysis, which were obtained by the usage of tools Fitcrack and Hashtopolis it was possible to observe this influence.
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Cyberattack Generator
Gregr, Filip ; Smékal, David (referee) ; Hajný, Jan (advisor)
This thesis is focused on developing a tool that is capable of generating cyber attacks. In the opening there are introduced some attacks using the ISO/OSI application layer protocols. Specifically, these are attacks known as Slowloris, RUDY, Slow Read, HTTP flood, and dictionary attack on the SSH. These attacks are implemented into an existing DoSgen Linux tool that already contains several famous network attacks. The main part of the thesis is devoted to the description of the tool and to the implementation of its own extension. The created tool is practically tested in an experimental enviroment against the Apache web server. Part of the thesis is the documentation for the improved DoSgen tool.
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Cracking of the Substitution Cyphers in Classical Cryptography
Kulich, Martin ; Doležel, Michal (referee) ; Stružka, Jaroslav (advisor)
The thesis provides a tool for automatic monoalphabetic substitution ciphers cracking using most common words dictionary. It is based on some previous solutions for english language which were not designed for cracking ciphertext without word divisions. This thesis is focused on cracking ciphertexts without word divisions. It also looks at specifics of czech language - declension and its influence on dictionary size.
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Network Attack Capture Using Honeyd Tool
Bláha, Lukáš ; Chmelař, Petr (referee) ; Drozd, Michal (advisor)
The bachelor thesis deals with Honeyd tool and its effectivity in capturing network attacks. At the beginning, there is a description of honeypots and its utilization in network security. An important part of the thesis is constituted by a practical implementation of network attacks and their analysis. The main goal is to create an extension for Honeyd tool which can emulate file sharing in operation systems Microsoft Windows XP, especially its free accessible part called null session. As results there are tests evaluating the level of detection of computer attacks by the created tool.
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Influence of Network Infrastructure on Distributed Password Cracking
Eisner, Michal ; Zobal, Lukáš (referee) ; Hranický, Radek (advisor)
Password cracking is a process used to obtain the cracking key through which we get access to encrypted data. This process normally works on the principle of the repeated try of attempts and their verification by making calculations of cryptographic algorithms. The difficulty of algorithms affects the time spent on solving of the calculations. In spite of various acceleration methods, it is often necessary to distribute the given problem among several nodes which are interconnected via the local network or the internet. The aim of this thesis is to analyze the influence of network infrastructure on the speed, the scalability, and the utilization during different attacks on cryptographical hashes. For these purposes, there was created an automatized experimental environment, which consists of distinctive topologies, scripts, and sets of testing tasks. Based on the results of the analysis, which were obtained by the usage of tools Fitcrack and Hashtopolis it was possible to observe this influence.
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Analýza bezpečnosti bezdrátových sítí vybraného ISP
JANOUCH, Lukáš
The aim of the theoretical part of this bachelor thesis is to create a comprehensive overview of security of Wi-Fi networks. The thesis deals with issues such as the importance of securing Wi-Fi networks, types of securing and their vulnerabilities. In the end of the theoretic framework, there is a list of common types of attacks on wireless networks and possible defense against them. The aim of the practical part of this thesis is to analyse and evaluate the security of the wireless networks of a chosen commercial ISP with the emphasis on the default configuration and based on the identified facts to propose a solution leading to the improvement of the current state.
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