The Kali Linux environment is based on the Debian Linux distribution focused on advanced computer network penetration testing. It is used to detect weaknesses and disadvantages of computer systems before hackers do it and exploit the access to data for their purposes. Each attack follows certain rules and procedures. With other words, information is collected and exploited to influence the target or to allow additional attacks. WLAN represents a wireless computer network that connects two or more devices with wireless communication. That is why there are various security weaknesses of such networks. To increase the security level, tests with Kali Linux have been carried out over various wireless network parameters. When a client knows the scope of the attack, he can adapt and act appropriately to prevent it. Using the Kali terminal and Wireshark has shown the lack of a hidden SSID, MAC filtering and WEP/WPA/WPA2 encryption. WEP can always be cracked, so it is considered unsafe, and WPA/WPA2 are currently considered cryptographically impenetrable with the existence of a strong unique key. In general, care should be taken when handling in a network, especially if public networks are used, and it is also advisable to use antivirus systems and firewalls.