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Securing IP PBX against attacks
Hynek, Luboš ; Krajsa, Ondřej (referee) ; Šilhavý, Pavel (advisor)
This master project focuses on the possibilities of protecting the most common free software PBX Asterisk, FreeSWITCH and YATE. In practice, it was verified the behavior of PBX in the attacks and suggested protection against them on one of the most popular distributions of Linux server on CentOS. Tool was created to simulate several types of attacks targeting denial of service. Both protective options PBX themselves and operating system capabilities are used in this work. Comparison was also the possibility of protection of individual PBX with each other. It also includes a brief description of the protocol, topology attacks and recommendation for the operation of softswitches.
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Analysis of the transmission properties of VDSL 2
Stejskal, Tomáš ; Šilhavý, Pavel (referee) ; Šedý, Jakub (advisor)
The aim of this work is to present the basic properties of VDSL2. Description of individual profiles and transfer options (speed, range, utilization, ...). The second part of this work is to create a program to control noise generator DLS-5800 and injector noise DLS-5410DC. The program is designed for remote control of these devices. It is programmed for the Microsoft Windows operating system in Visual Studio 2010 in C + + using the Winsock library. The program that is able to read noise profiles and change their parameters.
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Serial communication
Novotný, Bohumil ; Šilhavý, Pavel (referee) ; Martinásek, Zdeněk (advisor)
Bachelor work is focused on the issue of a serial communication interface RS-232,USB, I2C and SPI, and also discusses the use of the laboratory module for experimental purposes. Laboratory module is designed with respect to the functional elements that will resist daily use of students. This work is detailed principles of serial communication in relation to each interface. The second part is devoted to method the module structure, functions of its individual components and functional solution output connectable to an oscilloscope and other measuring devices.
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G.mgfast transmission technology
Rada, Dominik ; Ježek, Jiří (referee) ; Šilhavý, Pavel (advisor)
The master thesis deals with G.fast and G.mgfast transmission technologies, including their parameters. The work deals with the principle of vector DMT modulation and the possibility of time duplex TDD and full-duplex FDX in two-way communication used in these technologies. The following is a description of the line using the KHM model, which is suitable for simulations in the transmission band using G.fast and G.mgfast technologies. Subsequently, the disturbing effects of crosstalk at the near end of NEXT and the far end of FEXT and their elimination with these technologies are discussing. Part of the work explains supporting calculations to determine the SNR and bit allocation to calculate the baud rate. The work describes the methods of compensation of crosstalk FEXT and NEXT, which affect the resulting baud rate. The work also includes an application for simulation of transmission speed as a function of distance for G.fast and G.mgfast technologies, allowing changing input parameters and adjusting the transmission bandwidth based on G.9700 and G.9701 standards. Also, in work, an application is created to display the compensation of the influence of the transmitted signal crosstalk FEXT and NEXT, which allow the import of measured crosstalk between individual participants. The issue of influencing crosstalk for accurate measurements in the laboratory is also discussing. An application in the MATLAB environment is creating to display the measured characteristics.
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Analysis of digital modulation robustness at various types of interference
Uher, Tomáš ; Šilhavý, Pavel (referee) ; Kubánková, Anna (advisor)
This bachelor thesis concisely describes essential type of modulation technique for transmission of binary signal. In first part there are summarized advantages and disadvantages for each described modulation technique. There are described proceeding of modulation and demodulation too. Selected digital modulations are tested for Gaussian, Rice and Rayleigh transmission channels. In final part there are compared theoretical and measured values and summarized analysis.
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Open source PBX security against attacks
Orsák, David ; Daněček, Vít (referee) ; Šilhavý, Pavel (advisor)
This master's thesis deals with open source PBX security against security attacks. In the theoretical part is detailed description of problematic about attacks that could be used on VoIP systems with high focus on the Denial of Service attack. Furthermore are in theoretical part described methods of security of initialization protocol SIP. Individual chapter is devoted to intrusion detection and prevention of IDS and IPS systems, focusing on Snort and OSSEC. In the practical part of the work was created generator of attacks against various PBX systems, which was subsequently used for detailed testing. Special tests of PBX system are then used against DoS attacks, for which was created protection in form of active elements consisting of IDS Snort & OSSEC. These are capable to provide protection in real-time. The protection was tested on particular PBX systems and in matter of comparison were measured possibilities before and after of security implementation. The output of this work is attacks generator VoIPtester and creation of configuration rules for Snort and OSSEC.
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Graphical user interface for Network Assessment Tool
Šrůtková, Karolína ; Šilhavý, Pavel (referee) ; Martinásek, Zdeněk (advisor)
This thesis is focused on design and implementation of graphical user interface for Network Assessment Tool which is used for measuring and evaluation of network parameters in order correct functionality of Skype for Business application. Theoretical part of the thesis describes chosen network parameters and network testing. Then this part covers information about Skype for Business and Network Assessment Tool. Practical part consists of the design and developing graphical user interface. Finally, the developed application is tested.
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Testing of IP PBX resistance against attacks using Spirent Avalanche tester
Zelenay, Martin ; Šedý, Jakub (referee) ; Šilhavý, Pavel (advisor)
This work explores, analyzes and rate infuence of VoIP attacks on open source pbx functionality. It describes how voice over IP attacks are achieved according to security standards. There are described concepts and basics of VoIP networks with orientation on facts necessary to understand analyzed actions and measurements in theoretical part. In practical part, there is described realization of attack tests according to instructions with first orientation on initial checking of testing device, pbx’s and security attack possibilities and then complex creation and testing of attack scenarios types such as fuzzing and denial of service attacks.
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Control of electronic systems via web interface
Dufek, Ladislav ; Šilhavý, Pavel (referee) ; Zeman, Václav (advisor)
This master thesis goes into problematics of design of an electronic device control system and its realization. First of all its overall conception is specified and potential hardware platforms are analyzed afterwards. Based on this analysis the system’s final conception is drawn up, the device’s circuit layout is created and finally a functional prototype is manufactured. The later part of this thesis describes the software accessories and tools. The principles of a chosen operating system, management application and webbased interface are described along with the problems of authentization to solve. The proposed solutions for the authentization-specific tasks gave rise to the final implementation of the authentization methods and techniques.
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