A Cisco cert will help but won't by any means make you a hacker. With knowledge in networking you could at least be aware of obstacles you may come across such as firewalls, ACLs, proxies, etc. Not all of that is covered in the CCNA level but you should come out of it with a basic understanding of network flow and client/server transactions. If you're going through the Cisco Academy you'll also get some exposure to Wireshark which is a decent packet sniffing tool. Once you know the networking basics it shouldn't be too extremely difficult to advance your knowledge on your own, or through more classes if your wallet permits.