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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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Automated Creation of Password Mangling Rules
Drdák, Dominik ; Zobal, Lukáš (referee) ; Hranický, Radek (advisor)
In the process of password cracking by a dictionary attack, the password repertoire is limited by the used dictionary. With the help of rules that can modify passwords from a dictionary, it is possible to extend such a dictionary with additional passwords. In order to maximize the benefits of these rules in password cracking, the rules can be generated based on existing data. Frequent patterns, such as capitalization, numbers at the end or frequently used substrings in passwords can be found in databases of leaked passwords. Based on the patterns obtained, a set of clever rules can be created that can significantly improve the success of a password cracking by dictionary attack. The gist of the work is based on this knowledge and presents specific methods for the implementation of these procedures. The work describes the design and implementation of such tool that can create a set of rules from existing passwords based on their similarity. The functionality of the tool and especially the benefits of the chosen method are shown experimentally.
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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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Analysis of the Possibility of Password Break through for RAR, ZIP and 7z Formats
Prustoměrský, Milan ; Přikryl, Zdeněk (referee) ; Hruška, Tomáš (advisor)
This Thesis deals with analysis of the possiblity of password breakthrough for common compression formats and password extraction from self-extraction archives used for malicious software. Structure of compression programs, ciphers and connection between cipher and archives is described. Common and specialized attacks on archives and ciphers are described. Structure of self-extracting archives and password location is used to create extractor of passwords in self-extracting archives.
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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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Automated Creation of Password Mangling Rules
Drdák, Dominik ; Zobal, Lukáš (referee) ; Hranický, Radek (advisor)
In the process of password cracking by a dictionary attack, the password repertoire is limited by the used dictionary. With the help of rules that can modify passwords from a dictionary, it is possible to extend such a dictionary with additional passwords. In order to maximize the benefits of these rules in password cracking, the rules can be generated based on existing data. Frequent patterns, such as capitalization, numbers at the end or frequently used substrings in passwords can be found in databases of leaked passwords. Based on the patterns obtained, a set of clever rules can be created that can significantly improve the success of a password cracking by dictionary attack. The gist of the work is based on this knowledge and presents specific methods for the implementation of these procedures. The work describes the design and implementation of such tool that can create a set of rules from existing passwords based on their similarity. The functionality of the tool and especially the benefits of the chosen method are shown experimentally.
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