Essay About Simple Unix Commands And Passwd File

Hacking Servers
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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 . 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 Ill 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
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. Its 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:
Then substitute the site you are trying to hack