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Hacking Servers: A
This is yet more hacking trick that you should know to protect your network.
By: Lord Dredd
I am asked at least 5 or more times a day by young, beginning "hackers", "How can I hack?" or "Is there a way to hack a web site?" Well there is. There are, in fact, literally hundreds of ways to do this. I will discuss a few in this text to get you started. Every hacker has to start somehow and hacking web servers and ftp servers is one of the easiest ways. If you are reading this I am assuming that you already have a basic knowledge of how web servers work and how to use some form of UNIX. But I am going to explain that stuff anyway for those of you who don't know.
Part 1: Simple UNIX Commands
Most DOS commands have UNIX and Linux equivalents. Listed below are some of the main commands you will need to know to use a shell account.
HELP = HELP
COPY = CP
MOVE = MV
DIR = LS
DEL = RM
CD = CD
To see who else is on the system you can type WHO. To get information about a specific user on the system type FINGER <username>. Using those basic UNIX commands you can learn all you need to know about the system you are using.
Part 2: Cracking Passwords
On UNIX systems the file that contains the passwords for all the users
on the system is located in the /etc directory. The filename is passwd. I bet
your thinking...."Great. All I have to do is get the file called /etc/passwd
and I'll be a hacker." If that is what you are thinking then you are dead
wrong. All the accounts in the passwd file have encrypted passwords. These
passwords are one-way encrypted which means that there is no way to decrypt
them. However, there are programs that can be used to obtain passwords from
the file. The name of the program that I have found to be the best password
cracker is called "Cracker Jack." This program uses a dictionary file composed
of thousands of words. It compares the encrypted forms of the words in the
list to the encrypted passwords in the passwd file and it notifies you when
it finds a match. Cracker Jack can be found at my web site which is at http://www.geocities.com/SiliconValley/9185
Some wordlists can be found at the following ftp site: sable.ox.ac.uk/
pub/wordlists. To get to the wordlist that I usually use goto that ftp site
then goto the American directory. Once you are there download the file called
dic-0294.tar.Z which is about 4 MB. To use that file it must be uncompressed
using a program like Gzip for DOS or Winzip for Windows. After uncompressing the file it should be a text file around 8 MB and it is best to put it in the same directory as your cracking program. To find out how to use Cracker Jack just read the documentation that is included with it.
Part 3: The Hard Part (Finding Password Files)
Up till now I have been telling you the easy parts of hacking a
server. Now we get to the more difficult part. It's common sense. If the
system administrator has a file that has passwords for everyone on his or her
system they are not going to just give it to you. You have to have a way to
retrieve the /etc/passwd file without logging into the system. There are 2
simple ways that this can sometimes be accomplished. Often the /etc directory is not blocked from FTP. To get the passwd file this way try using an FTP
client to access the site anonymously then check the /etc directory to see if
access to the passwd file is restricted. If it is not restricted then download
the file and run Cracker Jack on it. If it is restricted then try plan B. On
some systems there is a file called PHF in the /cgi-bin directory. If there
is then you are in luck. PHF allows users to gain remote access to files
(including the /etc/passwd file) over the world wide web. To try this method
goto your web browser and type in this URL: http://xxx.xxx.xxx/cgi-bin/phf?Qalias=x%0a/bin/cat%20/etc/passwd
Then substitute the site you are trying to hack for the xxx.xxx.xxx.
For example, if I wanted to hack St. Louis University (and I have already) I
would type in http://www.slu.edu/cgi-bin/phf?Qalias=x%0a/bin/cat%20/etc/passwd
Don't bother trying www.slu.edu because I have already done it and told them about their security flaw.
Here's a hint: try www.spawn.com and www.garply.com If the preceding to methods fail then try any way you can think of to get that file. If you do get the file and all the items in the second field are X or ! or * then the password file is shadowed. Shadowing is just a method of adding extra security to prevent hackers and other unwanted people from using the password file. Unfortunately there is no way to "unshadow" a password file but sometimes there are backup password files that aren't shadowed. Try looking for files such as /etc/shadow and other stuff like that.
Part 4: Logging In To "Your" New Shell
OK....This is where you use what you found using Cracker Jack.
Usernames and passwords. Run your telnet client and telent to the server that
you cracked the passwords for, such as www.slu.edu. When you are connected it
will give a login screen that asks for a login names and password and usually
information on the operating system that the server is using (usually UNIX,
linux, aix, irix, ultrix, bsd, or sometimes even DOS or Vax / Vms). Just type in the information you got after cracking the passwd file and whatever you know about UNIX to do whatever you feel like doing. But remember that hacking isn't spreading viruses or causing damage to other computer systems. It is using your knowledge to increase your knowledge.
Part 5: Newbie Info
If you feel that you have what it takes to be a serious hacker then you must first know a clear definition of hacking and how to be an ethical hacker. Become familiar with unix environments and if you are only just starting to learn to hack, visit a local library and find some books on various operating systems on the internet and how they work. Or you could go to a book store and buy a couple internet security books. They often explain how hackers penetrate systems and that is something a beginner could use as an advantage.