To be really a high level hacker requires a vast amount of knowledge and it can easily put someone new to the subject into a state of overwhelm. You will hear you should learn networking, a number of operating systems inside and out, programming, various tools, etc…, the list goes on.
As that old dumb joke goes, “how do you eat an elephant?” well that’s really the perfect approach and I recommend tackling it “one bite at a time”.
I really recommend starting off with the study of TCP/IP, in fact I made that recommendation over a year ago on this forum. Why TCP/IP? Because this is “language” that computers use to speak to each other. Without a protocol to communicate, there is no hacking in the remote sense. At one time in the past computers didn’t need to communicate to each other, but now networking has made it a must and TCP/IP is the adopted protocol.
I am not trying to say hacking is just accessing a remote machine, but it certainly is a very important aspect of it and as hackers we should understand how that works inside and out.
One really good book that I recommend for a good basic understanding is TCP/IP jumpstart, by Andrew Blank. It’s a Sybex book and really puts the protocol in easy to understand analogies and is perfect for the beginner.
Once that book has been started I really recommend starting to play with a tool. The best tool to start with is Nmap. Nmap is the perfect example of how a tool can play with and alter normal TCP/IP transmissions. Knowing how to play and change normal transmissions with this protocol is a must for seeing through today’s firewall and IDSs. Nmap is also the number one hacker tool and its mastery is a fundamental skill so the sooner one gets it under their belt the better. When I say number one, I state that because I just about never find a hacker that doesn’t use it. Once in a while a hacker might say they don’t use it because they have written their own tool, but once I see that tool, its usually a watered down version of Nmap, lol.
That’s my recommendation for what its worth. Start off with a good study TCP/IP and start playing with Nmap. Don’t rush through this. Spend sometime and really get the feeling you have a good understanding of both. I can assure you it will pay off huge dividends as you go deeper into this subject.