I have an Alfa AWUS036NHA wifi external card. I use Kali Linux 2.0 with Wifite. And i'm unable to capture any handshake. The program deauthenticate the device correctly but no handshake captured. I tried it with a lot of different networks but i can't figure out the problem. Can someone help me?
You need a good signal to capture. -69 or less, tending toward 0. You can remove some noise by placing your sniffer card inside a metal container (like a BUCKET), with the top facing toward the target WLAN. The container must have a diameter of at least 12.5cm (2.4GHz wavelength). Yes, I know cantennas have a smaller diameter, just trust me on this. You can also use a metal bowl, or one of those meshed bowls for keeping fruit in, as long as it has a fairly fine grid.
Copper, gold and silver are best. Aluminium is pretty good. Steel is not so good, but better than lead. Hehe. You are not building an antenna, you are building a filter for interference. Most of the irrelevant radiation around you will not pass into your sniffer card.
silver 422 W/mK copper 402 W/mK gold 298 W/mK aluminium 226 W/mK steel 73.3 W/mK lead 34.8 W/mK
Your mother's silverware? Use it.
ALFA cards have sort of poor reception, it's best to use nice expensive radio card for sniffing. Make sure you are running off battery on your laptop, or there's gonna be even poorer reception. It also helps to change the case to one made from aluminium (connect it to ground).
Remember to deauth using one wifi card, and pick up the handshake using another. Wifite is weird. Just use kismet.
Amazingly, the adapter is now as good as my builtin mini pci card for wireless, although a bit slower to respond when issuing commands to change modes etc. Everything electronic from china should be heatsinked. Perhaps it will also help A LOT to put it in a metal box!
Edit2: Poked around a bit more, and it definitely helps to use short USB cables with ferrite bead(s). You can buy these cables with beads attached (typically used for harddisks), or just buy snap-on ferrite beads and attach them one by one until you stop seeing improvement in reception.