How hacker could own a system
hi! i usually wonder how hacker can break in one's system, than through this site i got limited knowledge like they use an open port for this purpose. But can they break in using any open port without a trojan's help like sub7? 2nd question is i know using of zonealarm can block the open ports but still some ports like http (i can't remeber its number), yahoo's or msn messenger ports, one have to open these ports in ordor to connect thier server. Question is is there any possibility that a hacker can break in your system using these open ports, if yes than HOW? hope for some good response.
Note;- I want to learn procedure of this security issue, not prevention method.