I really enjoy reading and researching about networking and pentesting. Recently I heard from a friend that there are ways that can be used to get into wireless networks without needing an adapter that supports monitor mode. He spoke about a Wireshark tweak but thats all he knew of. Hopefully someone here knows. anyway Are there any alternative methods?
Practically speaking, no.
In order to break a WPA2-Personal network you need to capture a four way handshake. There are basically two methods to do this. In one case you simply eavesdrop while others connect, and when that connection is established the four way handshake occurs. The other option is to kick a client off of the network and again, capture the four way handshake.
In both cases you are capturing traffic that is not destined for your machine (mac address) and in most cases, you do not know the mac addresses of the clients that are currently on the network. For these reasons in almost every practical case to break into a WPA2 network you will need to put your network adapter into monitor mode*.
For WPA2 enterprise the scenario is completely different, but the answer is the same. In order to attack the network you need to set up a rouge AP. Although the steps for creating this AP technically don't dictate that you need to put your card into monitor mode; in order to know all of the configurations to successfully carry out the attack you will need to put your wireless interface into monitor mode.
*Note: If you do know the mac address of a client, and you have already connected to the network - it is possible to change your mac address to that of another client and receive their packets without the use of monitor mode. But then you're not really attacking the network are you?