Analysis of attacks in local wireless networks

Namen diplomskega dela je predstaviti protokol Wi-Fi, njegove varnostne standarde in napade z zanikanjem storitve (angl. Denial of Service - DoS). Omrežje Wi-Fi deluje brezžično preko radijskih valov, zato lahko vsak prestreže poslane pakete in vidi njihovo vsebino. Za večjo zasebnost in stabilnost v Wi-Fi omrežjih so bili v protokol vključeni različni varnostni standardi. V okviru diplomskega dela so razloženi varnostni standardi WEP, WPA, WPA2 in WPA3. V teoretičnem delu so predstavljene različne vrste napadov, ki jih je možno izvajati v brezžičnih lokalnih omrežjih. Postavili smo testno okolje, v katerem smo s pomočjo brezžičnega usmerjevalnika TP-Link Archer C80 postavili omrežje, ki uporablja mešanico standardov WPA2 in WPA3. Na omrežje je bilo povezanih več naprav. Nad postavljenim omrežjem in napravami smo demonstrirali napad z deavtentikacijo, napad s poplavljanjem in napad s simulacijo podvojene naprave. Napad z deavtentikacijo je uspešno prekinil povezavo starejših naprav z omrežjem. Napad s poplavljanjem ni prekinil niti ni oslabil povezav v Wi-Fi omrežju. Napad s simulacijo podvojene naprave je eni napravi uspešno preprečil dostop do medmrežja, vendar ji ni prekinil povezave z omrežjem. V zaključku predlagamo še načine obrambe pred napadi in možne izboljšave napadov.The aim of the thesis is to present the Wi-Fi protocol, its security standards and Denial of Service (DoS) attacks. A Wi-Fi network works wirelessly over radio waves, which means anyone can intercept sent packets and see their contents. For greater privacy and stability in Wi-Fi networks, various security standards have been included in the protocol. The WEP, WPA, WPA2 and WPA3 security standards are explained as part of the thesis. The theoretical part presents various types of attacks that can be carried out in wireless local networks. We set up a test environment using a TP-Link Archer C80 wireless router to set up a network using a mix of WPA2 and WPA3 standards. Several devices were connected to it. We demonstrated a deauthentication attack, a flooding attack, and a duplicate device simulation attack over the deployed network and devices. The deauthentication attack successfully disconnected older devices from the network. The flooding attack did not disconnect or weaken Wi-Fi connections. And the duplicate device simulation attack successfully prevented one device from accessing the internet, but did not disconnect it from the network. Finally, we suggest ways to defend against attacks and possible improvements of attacks