WiFi Sniffing: Can Attackers See Your Network Traffic?

TL;DR

Yes, an attacker can sniff physical network traffic through WiFi under certain conditions. This is usually done by putting the WiFi adapter into monitor mode and capturing packets. Modern encryption (WPA2/3) makes it harder to decrypt the data, but not impossible. Using strong passwords, keeping firmware updated, and being aware of rogue access points are key defenses.

How an Attacker Sniffs Traffic

1. Monitor Mode: The attacker needs a WiFi adapter capable of entering “monitor mode”. This allows the adapter to listen to all traffic on a channel, not just traffic directed at its own MAC address. Most built-in WiFi adapters don’t support this; an external USB adapter is usually required.
2. Channel Hopping: WiFi networks operate on different channels. An attacker will often “hop” between channels rapidly to capture traffic from multiple networks simultaneously.
3. Packet Capture: Tools like Wireshark or Aircrack-ng are used to capture the raw network packets. These tools record all the data transmitted over the airwaves.
4. Decryption (if encrypted): If the network is secured with WPA2/3, the attacker will attempt to crack the password to decrypt the captured traffic. This can be done using brute-force attacks or dictionary attacks against the handshake. WEP networks are easily cracked and offer no real security.

Tools Used by Attackers

• Wireshark: A powerful packet analyzer used to inspect network traffic in detail.
• Aircrack-ng Suite: A collection of tools for auditing WiFi networks, including capturing handshakes and cracking passwords.

  airmon-ng start wlan0

  (starts monitor mode on interface wlan0)

• Reaver: Specifically designed to crack WPA/WPS networks.

How to Protect Yourself

1. Strong Passwords: Use a long, complex password for your WiFi network (at least 12 characters with mixed case letters, numbers and symbols). Avoid using easily guessable words or personal information.
2. WPA3 Encryption: If your router and devices support it, use WPA3 encryption. It offers significantly stronger security than WPA2.
3. Keep Firmware Updated: Regularly update the firmware on your router to patch security vulnerabilities.
4. Disable WPS: WPS (WiFi Protected Setup) is often vulnerable to attacks. Disable it in your router settings if you don’t use it.
5. Hidden SSID (Network Name): While not a strong security measure, hiding your SSID can make it slightly harder for attackers to find your network. However, it doesn’t prevent determined attackers.
6. MAC Address Filtering: Allow only specific devices with known MAC addresses to connect to your network. This is easily bypassed by MAC address spoofing but adds a layer of complexity for attackers.
7. Rogue Access Point Detection: Be cautious when connecting to public WiFi networks. Attackers can set up fake access points (evil twins) to intercept your traffic. Look for HTTPS websites and use a VPN.
8. VPN (Virtual Private Network): A VPN encrypts all of your internet traffic, protecting it even if the WiFi network is compromised.

Is Wired Better?

Yes! Using an Ethernet cable to connect directly to your router provides a much more secure connection than WiFi. It eliminates the risk of wireless sniffing attacks.