Wireless network attacks What type of attack is most common?

It would probably be packet sniffing, although you do need to be rather close to your target to do that. My personal weapon of choice for penetration testing I have owner's consent though is a man in the middle attack where I get between the computer and the firewall and tell each one that I am the other to let them send me information. Also from afar most people would just Denial of Service your network which is sending so much information that it can't serve your users.