Modern wireless communication standards require a deep understanding of how they work, especially in the context of information security. Kali Linux is a specialized operating system distribution designed for cybersecurity and pentesting professionals. This tool allows network administrators to identify weaknesses in equipment configurations before attackers can exploit them.
In this article, we will examine the technical aspects of security analysis of encryption protocols and authorization mechanisms. It is important to understand that any scanning or testing of other people's networks without the owner's written permission is illegal. Ethical hacking implies work exclusively within the framework of the law and with the consent of the infrastructure owner.
The main goal of this training is to understand how handshake interception and brute-force passwords work, so you can reliably protect your own network. We'll examine the tools included in the standard distribution kit and explain their logic. This knowledge is essential for every system administrator to build resilient security.
Preparing equipment and software environment
The first step in the security audit process is to properly configure the working environment. Standard built-in laptop modules often do not support the mode. monitoring, which is critical for capturing data packets. You will need an external USB adapter with a chipset capable of switching to monitor mode, for example, based on Atheros AR9271 or Ralink RT3070.
After connecting the adapter, you need to make sure the system has correctly identified the device. In the terminal, use the command ip link or iwconfig to view the list of interfaces. If the adapter is displayed as wlan0 or similarly, you can start configuring it to work with low-level protocols.
β οΈ Attention: Switching your network card to monitoring mode may disrupt your current internet connection. It's recommended to have an alternative connection or perform the work on an isolated test bench.
The most commonly used utility to manage wireless interfaces in Kali Linux is aircrack-ngIt is a set of tools for assessing the security of wireless networks. Before starting, it is necessary to stop processes that may interfere with packet capture, such as NetworkManager.
βοΈ Audit readiness check
Wireless space analysis and target search
Once the equipment is prepared, the next step is reconnaissance. You need to locate available access points and evaluate their security parameters. To do this, use the command airodump-ng, which puts the card into passive listening mode. This allows you to see not only open networks but also hidden SSIDs.
While scanning, pay attention to the channels used by neighboring routers and the signal level (RSSI). The closer you are to the signal source, the more stable the connection will be during tests. It's also important to identify the encryption type: WEP is outdated and extremely vulnerable, while WPA2 and WPA3 are modern standards.
- π‘ SSID β the name of the wireless network that is displayed when searching for devices.
- π BSSID β a unique MAC address of the access point, required for targeting attacks.
- πΆ Power β the signal strength level indicating the quality of communication with the target.
- π’ Data β the number of captured data frames, the growth of which is important for analysis.
Scan results are displayed in real time, allowing the operator to select the most suitable target for further analysis. Data is recorded in files with the extension .cap or .pcap, which can then be analyzed in more detail. Effective reconnaissance saves time and improves the efficiency of subsequent testing stages.
Monitor mode and packet injection
The key to working with wireless networks is the ability to not only receive but also emit your own packets into the air. The card's standard mode only allows you to exchange data with the access point you're connected to. monitoring Allows the card to hear all packets within range, whether they are intended for you or not.
To switch the interface to the desired mode, use the command airmon-ng start wlan0After this, the interface can be renamed, for example, to wlan0monIn this state, the card is capable of capturing handshakesβthe process of client authentication when connecting to the network. This handshake contains the password hash, which is then analyzed.
sudo airmon-ng start wlan0sudo iwconfig
Mode check: Mode:Monitor
However, simply waiting for someone to connect to the network is ineffective. To speed up the process, a deauthentication technique is used. Using a utility aireplay-ng Special frames are sent that forcibly terminate the connection between the legitimate client and the router. The client device automatically attempts to reconnect, generating a new handshake, which is then intercepted by the attacker.
β οΈ Attention: Sending deauthentication packets en masse may be interpreted by providers and security systems as a DDoS attack. Use this technique only on your own equipment in a lab setting.
WPA2 Attack and Handshake Analysis
WPA2 Personal is considered the de facto standard for home networks, but it has a fundamental vulnerability related to human error. If the password is long and complex, it is virtually impossible to crack. However, if the password is short or contains dictionary words, it can be brute-forced.
After successfully capturing the handshake (file .cap contains a 4-way handshake), the cryptanalysis stage begins. The tool aircrack-ng Allows you to start the password cracking process using pre-prepared dictionaries. The most popular dictionaries, such as rockyou.txt, contain millions of frequently used character combinations.
| Parameter | Description | Impact on safety |
|---|---|---|
| Password length | Number of characters in a keyword | Critical: Each additional character exponentially increases the time it takes to search |
| Complexity | Use of special characters, numbers, case | High: Makes simple dictionary attacks difficult to use |
| WPS | Wi-Fi Protected Setup | Critical: The presence of a Pixie Dust or brute-force PIN vulnerability makes the network vulnerable regardless of the password. |
The brute-force process can take anywhere from a few seconds to indefinitely, depending on the password's complexity and the computing power of the hardware. Modern graphics cards can process millions of hashes per second, making short passwords useless. This is why The minimum recommended password length for WPA2 is 12-15 random characters..
WPS vulnerabilities and methods of exploitation
WPS (Wi-Fi Protected Setup) technology was developed to simplify connecting devices, but it has become one of the biggest security holes in Wi-Fi. The mechanism uses an 8-digit PIN, which theoretically allows for 100 million combinations. However, due to a flaw in the protocol design, verification occurs in two stages, reducing the number of attempts to 11,000.
A tool is used to test the WPS vulnerability in Kali Linux reaver or its more modern version bullyThese utilities automatically attempt to guess the PIN code. If the router doesn't have brute-force protection (blocking after several unsuccessful attempts), the password can be obtained within a few hours.
Why is WPS so easy to hack?
The protocol divides the 8-digit PIN into two parts. First, the first four digits are checked (10,000 possibilities), then the second three (1,000 possibilities, since the last digit is a checksum). This reduces the brute-force time from years to hours.
Even if WPA2 is enabled on the router with a complex password, enabling WPS negates all security. An attacker only needs to know the PIN to access the network and obtain the master password in cleartext. Therefore, the first step in strengthening the security of any access point should be completely disabling WPS in the administrator settings.
Network protection and hacking prevention
Understanding attack methods allows you to develop an effective defense strategy. First and foremost, it's essential to avoid using outdated encryption protocols. WEP should be avoided entirely, as it can be cracked in minutes even on low-end hardware. WPA/WPA2 Mixed Mode is also not recommended, as it can reduce the overall security level to the WPA standard.
The ideal configuration at the moment is to use WPA3, if your hardware supports it. This standard implements protection against brute-force attacks (SAE β Simultaneous Authentication of Equals) and improves encryption on open networks. If WPA3 is unavailable, use WPA2-AES with a long, complex password that does not contain personal information or dictionary words.
- π‘οΈ Disabling WPS β a mandatory action for all routers.
- π Firmware update β closes known vulnerabilities in the router software.
- π« MAC address filtering β an additional measure, although it is not a reliable protection (addresses are easy to forge).
- π Power reduction - reduces the signal range, making it difficult to intercept outside the premises.
Regularly auditing your network using the tools described above will help ensure the effectiveness of your measures. You can attempt to hack your network yourself; if this fails within a reasonable time, your protection is working properly. Security is a process, not a one-time action.
Legal aspects and ethics of use
Using Kali Linux tools to infiltrate networks that don't belong to you is a criminal offense in many jurisdictions. Computer information laws strictly regulate access to data. Even if the network isn't password-protected (open), attempting to gain control of devices within it or intercepting traffic may be considered unlawful interference.
Information security specialists work under signed non-disclosure agreements and Scope of Work (SoW) to conduct tests. Any actions outside the agreed-upon list of IP addresses or domains are considered a breach of contract and a violation of the law. White Hat Hackers always act transparently and in a documented manner.
β οΈ Attention: Cybersecurity legislation is constantly changing. Before beginning any work, familiarize yourself with the current regulations in your region. Using sniffers in public Wi-Fi zones (cafes, airports) without the permission of the infrastructure owner is prohibited.
Learning Kali Linux should be done for educational purposes and to protect your own systems. Creating virtual labs and using your own routers and clients is the only safe and legal way to gain skills. The user is solely responsible for actions taken using the acquired knowledge.
Is it possible to hack Wi-Fi from an Android phone?
Technically, this is possible, but it requires root access and specific hardware. Most built-in Wi-Fi modules in smartphones don't support monitor mode or packet injection. This typically requires an external USB adapter and OTG support, making the process cumbersome compared to using a laptop running Kali Linux.
How long does it take to crack an 8-character password?
The time it takes to crack a password depends on the complexity of the characters and the hardware's power. If the password consists only of numbers, it will be cracked instantly. If both letters and numbers are used, a modern video card can brute-force all combinations in a few hours or days. A password consisting of 8 random characters (including special characters) can take years to crack.
Does hiding the SSID protect against hacking?
No, hiding the SSID (network name) is not a security measure. The network continues to broadcast control frames, which are easily detected by tools like airodump-ng. This only creates the illusion of security and can cause connection issues for legitimate devices.
What is WPA3 and is it worth switching to?
WPA3 is the latest security standard that addresses many of WPA2's vulnerabilities, such as handshake attacks. The upgrade is worth it if all your devices support this protocol. However, in compatibility mode (WPA2/WPA3 Mixed), some benefits may be lost.