Wireless Security - Layer 2 DoS


These attacks are the ones which are most likely launched by malicious attackers. The main idea behind this attack is to temper the 802.11 wireless frames and inject (or retransmit) them into the air.

The most common types of Layer 2 DoS attacks involve spoofing of disassociation or de-authentication management frames. The reason, why it is so efficient is that, those frames are NOT the request frames but notifications!

Layer 2 DoS Attacks

Because authentication process is a pre-requisite for association (as illustrated above), a de-authentication frame will automatically disassociate the client as well.

This kind of attack maybe (once again), started using aireplay-ng tool. Can you see how powerful this tool is?

Targeting once again my home network with ESSID of "home_e1000", I first check connected clients with airodump-ng.

ESSID of Home

My smartphone is the device connected to home_e1000 network with MAC address 98:0D: 2E: 3C:C3:74. I then issue a de-authentication DoS attack against my smartphone as shown in the following screenshot −

Deauthentication DoS Attack

The result, once again, my target device at home (smartphone) becomes disconnected from the Wi-Fi network.

Mitigation technique against those type of attacks is to use an 802.11w-2009 Standard Management Frame Protection (MFP). In simple words, this standard requires that management frames (like disassociation or de-authentications frames) are also signed by a trusted AP, and if they come from a malicious client or a fake AP, they should be neglected.