Ethernet controller: Atheros Communications Inc. AR2413/AR2414 Wireless Network Adapter [AR5005G(S) 802.11bg]

Test & try:

sudo rmmod ath5k
sudo modprobe  ath5k nohwcrypt
After OK, make peranent:

sudo sh -c "echo 'options ath5k nohwcrypt' >/etc/modprobe.d/custom-wireless.conf"
Source: http://discoverylinux.wordpress.com/2012/06/02/guida-problemi-con-wifi-atheros-e-ubuntu-12-04-lts-pengolin/