An essential aspect of Wi-Fi vulnerability assessment is exercising your WLAN's policies and countermeasures, looking for blind spots, mistakes, and attacks that can overwhelm your APs, controllers, or IPS. In other words, attacking yourself to validate your defenses. There are many tools that can be used for this, but one of our favorites is MDK3, a command-line utility that can guess hidden SSIDs and MAC ACLs, look for clients vulnerable to authentication downgrade, initiate Wi-Fi Beacon, Deauth, and TKIP MIC DoS attacks, and generally wreak havoc.