How to close open backdoors for hackers?
A resellers client got jail shell and now he says that his client found more than 20 backdoors. He used just nmap and telnet to get the password of all users. - How could he do that? I thought that jail shell were more secure. But more important, how do I close these backdoors - what can I do to find these backdors and then close them. I hope that someone knowing about these things will lend a helping hand.Thanks
John