Keeping from getting caught
Hacking is a gray area, as far as what exactly is legal, and what exactly isn't. Even if you follow the hacker code of ethics (never harm), you are still quite possibly breaking one or more laws. Let me just say that if you are already on a system, with someone else's login name and password, you are blatantly breaking a few laws. Nuking is also illegal. IP and port scanning are not illegal, though they definitely cause suspicion. In the past, measures to keep oneself safe included hacking from payphones, splicing your neighbor’s line, 'bouncing' your call (explained later), and even using programs such as Modem Jammer. Now, you should use one or more of these methods to keep from being physically traced, and another to keep from being traced over the Internet (to your ISP). The best and probably easiest way to do this is use someone else's account, preferably on a different ISP. This is much easier to do that one might expect. Shoulder surf someone typing in his or her login/password, do a little social engineering (explained later), or even brute forcing to get a valid account. There are even programs out there that if run on a machine used to access the Internet via a dial-up (with an ISP) it will give you the password. One such example is Dripper (available at The CyberUnderground). As far as physically tracing you goes, if you are using someone else's account you are sort of safe. If you have hacked into a system with a low-level account (a 'guest' account, for example) and just got yourself root (see definition above), you should seriously consider adding a few methods of security before reconnecting. To hack from a payphone, get an acoustic coupler for your modem, set the receiver on it, and just dial out. Bouncing your call means basically calling a modem somewhere that is designated as an 'outdial', meaning once connected, any modem commands you issue will go to it, so you can dial from it somewhere else. If you are traced - it will be to that modem. This can be defeated though, so it’s a good idea to bounce calls off a few outdials. Outdials are pretty hard to find, but are most common on X.25's and other PSN's (for more info on outdials, read any other hacking text, like "The Neophyte’s Guide to Hacking," or "The Newbie's Handbook."
Anther security method (similar to bouncing your call) is bouncing your IP attack. Meaning - telnet to system that supports telnet itself - then telnet to your target. Finding and obtaining access to one of these is difficult for a new hacker, so I'll go into greater detail on this later. Another effective method to having your IP address logged into the system you're connected to (and thereby "busted,") is bouncing your packets off a Wingate host. Wingate is a server software program that acts kind of like a proxy server and firewall all in one (see above for definitions). As with a generic proxy server, all computers in the office that the Wingate computer is in connect to it to get to the Internet - and you can do the same. All you need is the IP address or domain name of a Wingate host. Telnet to it, and type the IP address you want to get to at the prompt you get. The IP address of the Wingate box will be logged as you connect - not your own. Finding Win Gates are very easy - just go to any hacker website (www.cyberarmy.com is a good one) and look at their database of WinGate's. You'll have to weed through lists of bad WinGate's though, so you may be better off getting a Wingate scanner and doing it yourself. If you're really smart, you'll bounce your packets off a few Win Gates before getting to your target.
As a rule of thumb, the amount of security you should be using is directly related to the seriousness of your hack. Though, you could be breaking many federal and state laws without even being close to having root access, and not even quite sure what you are doing. It cannot be stressed enough: be as safe as possible.
TCP/IP and the Client/Server model
Transfer Control Protocol/Internet work Protocol. The 'language,' or means for which packets are exchanged over the Internet, or any intranet. TCP/IP is nothing more than a set of rules and regulations that specifically define exactly how data is transferred between computers on a network. This protocol has several sub-protocols, known as the TCP/IP protocol suite. To utilize any of these sub-protocols, you just need a client of that. For example, Windows 95 and above has a built-in FTP and Telnet client (a client, when referring to a protocol, is a program that lets a user utilize that protocol). In this section I will explain each of these sub-protocols, and other protocols used over the Internet.
One concept that it is imperative you understand is the Client/Server model. Every protocol is utilized with software. For example: HTTP (Hyper Text Transfer Protocol, the protocol used to transfer HTML web pages to and from your computer [this is why it is at the beginning of URL's you visit] ). This protocol is put to use by software. This software has two pieces, a client side and a server side. When you type in a URL or click on a link, you are using a HTTP client software program (a browser) to request a copy of a particular web page. Then, the server of the URL you requested has HTTP server software that receives the request (in the form of packets), and provides you with a copy of it, by sending it back to your computer. A server side software package is also called a service, and is accessed via ports. A port is a "virtual channel" used to transfer packets of a specific protocol between a client and a server. When you hear the term 'port scanning,' what is being referred to is the scanning for protocol, or services. Also, each port (service installed on the server in question) has a number assigned to it (e.g.: telnet is generally number 23). At any rate, think of client side software as the requestor, and the server side software as the provider.
PPP. There are many protocols, most of which discussed here are used over the Internet's high-speed digital lines. However, there are lots of protocols used over regular analog phone lines, used before the Internet was a major computing tool. These include Kermit, Xmodem, Ymodem, etc, and all have parallels in the TCP/IP protocol suite. However, the only "analog phone line" one I'll cover is PPP. PPP (Point to Point Protocol) is the protocol used to connect to your ISP's server, who intern sends and receives TCP/IP packets over the Internet for you. SLIP is similar, but not as effective and as widely used. Basically, the way you are able to communicate with the digital network of the Internet is that your ISP translates TCP/IP packets to PPP so they can travel over phone lines, and vice versa.
Telnet. Let's start at the basics - on, say, a UNIX platform, there is one or more UNIX boxes - the computer that does the processing and holds all the data (files, applications, the OS, etc) which is the computer on the network that you are most likely trying to hack into. Then there are a slew of dumb terminals directly connected to it. A dumb terminal consists of nothing more than a monitor and a keyboard - the UNIX box handles everything a user types/does on a dumb terminal. Now, telnet is a protocol/application that allows people to connect to a computer remotely (over a phone line or the Internet) and processes data locally - meaning when you connect to a UNIX boxx via telnet, it just as if you were at a dumb terminal directly connected to the UNIX box. Telnet is the protocol you will be using to access the computer you are hacking into.
FTP. File Transfer Protocol. This is the protocol used to transfer files between computers over the Internet. Whether you are downloading password files or uploading changes to their HTML files, you will do it through FTP. To start an FTP session, you need to log in to the service with an FTP client, just as you would with Telnet. More on this later. Incidentally, the later browsers from Netscape and Microsoft have an FTP client built in. To use it, type 'ftp' instead of 'http' in your browser.
SMTP. Simple Mail Transfer Protocol. This is the protocol used to send and receive email. If you connect to a SMTP port (by telnetting into it) you can issue SMTP commands. When you send an email, along with the actual letter go along its protocol. This means that the SMTP packets (made up of your letter and other protocol-specific data) connects to port 25, and issues the appropriate commands to the SMTP service in order for the letter to reach its recipient. You can also connect to this port and issue these commands manually. The use of this could be sending email and changing the sender address to someone else (possibly the recipients employer). Also, with the VRFY command, you can find out whether or not a particular account (login name) exists on the network in question. Use the HELP command to familiarize yourself with the various SMTP commands.
HTTP. Hyper Text Transfer Protocol. This, again, is the protocol used to transfer HTML pages back and forth between two computers.
Finger. This protocol (also a UNIX utility) is used to obtain information about users on a remote machine. With a finger client, you can see who's logged on currently, and can find specific information about a specific user.
DNS. Domain Name Service. If a computer has this port open, it generally means that this particular computer is a domain server of that network (the spokesperson, if you will). If you were to telnet to a network/domain, and didn't specify a computer (e.g.: hackers.com, instead of comp3.hackers.com) you would by default be connected to one of the name servers of that network.
NBT. This stands for Net BIOS over TCP/IP, and is what Windows networks use. Another name for this is 'nbsession,' which generally indicates Net BIOS used over a Wide Area Network (such as the Internet), being that Net BIOS by itself (without TCP/IP) cannot be used over a WAN.
SNMP, UDP, ICMP, SMB, NetBEUI, POP. These, along with many other protocols are used regularly over the Internet as well. It is not in the scope of this text to explain them all, so I encourage you to research them and the others I've covered in more detail.