A modern approach to information security requires a deep understanding of how wireless networks operate. Administrators and penetration testers often use the operating system Linux to conduct legitimate audits of corporate and home networks. This is necessary to identify weaknesses in equipment configurations before they can be exploited by attackers.
Using distributions like Kali Linux or Parrot Security OS provides access to a powerful set of traffic analysis tools. It's important to understand that all actions described below must be performed exclusively on your own equipment or under a formal security testing contract. Any unauthorized interference with other people's networks is illegal.
In this article, we'll examine the technical aspects of wireless adapter monitoring and analyze the vulnerabilities of encryption protocols. You'll learn how professionals evaluate password strength and why old security standards are no longer considered reliable. This will allow you to better protect your infrastructure.
Preparing equipment and environment for audit
The first step in security testing is selecting the appropriate hardware. Not all wireless network cards support the features required for in-depth analysis. A critical parameter is the ability to switch the chipset to monitoring mode (Monitor Mode), which allows the card to capture all packets in the air, ignoring addressing.
The most stable operation in the Linux environment is demonstrated by adapters based on chipsets from Atheros, Ralink and some models RealtekBuilt-in laptop modules often have proprietary drivers that block low-level access. Therefore, professionals prefer to use external USB adapters with supported open-source drivers.
β οΈ Attention: When using virtual machines (VirtualBox, VMware), ensure the USB adapter is forwarded directly to the guest OS. Virtualization of the host's wireless interface often fails to provide the necessary functionality for packet injection.
After connecting the device, you need to ensure that the operating system has correctly detected the hardware. To do this, use the utility lsusb or iwconfigIf the adapter appears in the list, you can proceed to configuring the software environment and checking the available commands.
Setting up monitoring mode and scanning the airwaves
To begin analysis, you need to set the interface to a mode that allows monitoring of the entire radio range. The standard operating mode (Managed) filters packets, leaving only those addressed to your device. Monitor mode removes these restrictions, turning the card into a passive sniffer.
The switching process is usually performed using a utility airmon-ng, included in the package aircrack-ngBefore starting monitoring, it is recommended to stop system processes that may conflict with the network card, such as NetworkManager or wpa_supplicantThis will prevent the interface from suddenly shutting down while you're working.
sudo airmon-ng check kill
sudo airmon-ng start wlan0
Once successfully launched, the command will create a new virtual interface, often called wlan0monThis is what we'll be working with further. Now you can scan for available access points to assess network density and the channels being used.
- π‘ iwlist β a classic utility for detailed scanning and obtaining technical information about neighbors.
- π‘ airodump-ng β a powerful tool for visualizing traffic in real time with the ability to save logs.
- π‘ wash β a specialized scanner for searching for networks with WPS enabled, which is often a weak link.
It's important to note that there can be hundreds of networks in the air. Filtering by the desired frequency range (2.4 GHz or 5 GHz) helps focus on the target infrastructure and avoid overloading the processor with unnecessary noise.
Analysis of vulnerabilities of encryption protocols
Wireless network security is directly dependent on the encryption protocol used. Historically, standards have evolved from a complete lack of security to modern authentication methods. Understanding the differences between WEP, WPA And WPA2/WPA3 critical for risk assessment.
Protocol WEP (Wired Equivalent Privacy) was considered completely broken over a decade ago. Its RC4 encryption algorithm contains fundamental flaws that allow the key to be recovered in minutes given enough packets. Using WEP is unacceptable under modern conditions.
More modern standards WPA2-PSK use an algorithm AES, which is cryptographically strong. However, the vulnerability often lies not in the algorithm itself, but in the complexity of the password. Brute-force attacks are based on intercepting the four-way handshake between the client and the access point, followed by an offline attack on the password hash.
| Protocol | Algorithm | Security status | Recommendation |
|---|---|---|---|
| WEP | RC4 | Critically low | Replace immediately |
| WPA (TKIP) | TKIP | Short | Replace with AES |
| WPA2 (AES) | CCMP/AES | High | Use complex passwords |
| WPA3 | SAE | Very tall | Recommended everywhere |
The protocol is also worth mentioning. WPA3, which implements brute-force protection using the SAE (Simultaneous Authentication of Equals) method. Even if an attacker intercepts the connection process, they won't be able to launch a brute-force attack without interacting with the access point each time, making the attack extremely difficult.
β οΈ Attention: Some older devices (IoT gadgets, printers) may not support WPA2/WPA3. For these devices, it's often necessary to create a separate guest network with client isolation to avoid compromising overall perimeter security.
Methods for checking password strength
In the context of Wi-Fi security, password strength testing involves attempting to brute-force a key using intercepted hashes. This isn't "hacking" in the literal sense unless you have the password itself, but rather a mathematical comparison. This is accomplished using specialized dictionaries and mutation rules.
The most popular tool for this task is aircrack-ngIt allows you to upload files with saved handshakes and test them against text files containing millions of combinations. The effectiveness of the method directly depends on the quality of the dictionary used and the computing power of the system.
aircrack-ng -w /path/to/dictionary.txt capture-file.capMore advanced tools such as Hashcat or John the Ripper, utilize the power of graphics processing units (GPUs) to speed up brute-force attacks by thousands of times. They support complex masks and rules that generate word variations (replacing letters with numbers, adding endings), significantly increasing the success rate of attacks on weak passwords.
What are Rainbow Tables?
These are pre-computed hash tables that allow you to instantly find the original text of a password based on its hash, if it exists in the database. They take up a lot of space, but are faster than a typical brute-force attack.
It's important to understand that a password less than 8 characters long, consisting only of numbers or common words, will be cracked almost instantly. Using long phrases with mixed-case and special characters makes brute-force time astronomical and economically unfeasible.
Vulnerabilities of WPS technology
Technology WPS (Wi-Fi Protected Setup) was designed to simplify device connections, but it became one of the biggest failures in the history of Wi-Fi security. The 8-digit PIN mechanism was vulnerable to a logical vulnerability that reduced the number of entry attempts from 100 million to 11,000.
Tool Reaver or its fork Bully Automate the PIN cracking process. The attack takes anywhere from several hours to a day, after which the attacker gains cleartext access to the network or learns the WPA master password. This works even if the WPA2 master password is extremely complex.
- π Design vulnerability: The PIN code is checked in parts, which allows it to be guessed step by step.
- π No blocking: Many routers do not block the device after multiple unsuccessful login attempts.
- π Reset counter: Some models reset the error counter after a reboot, allowing the attack to continue.
The only reliable way to protect against this threat is to completely disable the WPS function in your router's settings. If the manufacturer doesn't provide this option (which is common with ISP devices), it's recommended to upgrade to an alternative firmware, such as OpenWrt, or replace the equipment.
Protocol-level attacks and deauthentication
One common technique for testing network resilience is a deauthentication attack. It's not aimed at gaining access to data, but rather serves to forcibly terminate the connection between the client and the access point. This allows, for example, to recapture a WPA handshake if the client hasn't reconnected for a long time.
This technique uses a deauthentication packet sent on behalf of the access point. Upon receiving this packet, the client device assumes the session is over and attempts to reconnect. At this point, a key exchange occurs, which is recorded by the sniffer.
β οΈ Attention: Continuously sending deauthentication packets may constitute a DoS (denial of service) attack and violate the law. Use this feature only briefly to test your own devices in an isolated environment.
There are also more sophisticated attacks such as Evil Twin (Evil Twin). In this case, a fake access point is created with the same name (SSID) as the legitimate one, but with a stronger signal. Users can automatically connect to it, after which their traffic can be intercepted or redirected to a phishing site.
Protecting against such attacks is difficult because they exploit the device's trust in the network name. Using enterprise-level protocols (802.1X) with certificates helps mitigate this threat, as the client will verify the authenticity of the authentication server, not just the network name.
Home and Office Network Security Strategies
After analyzing the attack methods, it becomes clear what steps need to be taken to strengthen security. The first and most important step is changing the default login credentials. The router administrator login and password should be changed immediately after purchase, as they are often shared across all device models.
A policy of regular firmware updates is essential. Manufacturers periodically release patches to address discovered vulnerabilities in the protocol stack. Ignoring updates leaves the network open to known exploits that already have ready-made tools for automated exploitation.
βοΈ Wi-Fi Security Checklist
Network segmentation provides an additional layer of protection. Guest networks should be isolated from the main network, which contains computers with sensitive data and NAS storage. This will prevent an infected guest device or vulnerable IoT device (such as a smart light bulb) from becoming a springboard for an attack on internal resources.
Frequently Asked Questions (FAQ)
Is it possible to hack Wi-Fi from an Android phone?
Theoretically, it's possible if the device is rooted and has a chipset that supports monitoring mode. However, in practice, mobile platforms are severely limited in their packet injection capabilities. Professional auditing requires a full-fledged OS, such as Linux on a PC.
Will hiding your SSID protect you from being hacked?
No, hiding the network name (SSID Broadcast) is not a security measure. The network name is still transmitted in service control packets and is easily read by any sniffer. This simply hides the network from the regular list of available connections for inexperienced users.
How reliable is a MAC address filter?
MAC address filtering only provides the illusion of protection. The address can be easily spoofed (cloned) by sniffing the airwaves and seeing an authorized device. An attacker can change their card's MAC address to an authorized one in a matter of seconds.
Does monitoring mode harm the wireless card?
The monitoring mode itself does not cause physical damage to the equipment. However, intensive operation under constant load and overheating can shorten the lifespan of any electronic component. It is recommended to take breaks during extended tests.
What should I do if my ISP's router doesn't have security settings?
In such cases, it's recommended to set your provider's device to Bridge Mode, if possible, and connect your own router with the appropriate security settings behind it. If Bridge Mode is unavailable, try accessing advanced settings through hidden pages or Telnet (you'll need to find specific instructions for your model).