*** My Favourite UNIX Commands ***
*** A List Of Some OF The Most Useful UNIX **
*** Hacking Commands, and Some Hints On Their Usage ***
*** Written By ZeeBee Australia Inc. 1990 ***
Ok UNIX freaks, here is a little list of helpful UNIX
commands and procedures which can be of much assistance in
gaining the fullest potential from any UNIX system.
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It is fun and often usefull to create a file that is owned
by someone else. On most systems with slack security ie 99% of
all UNIX systems, this is quite easily done. The chown command
will change any of your files to make someone else the owner.
Format is as follows:
chown ownername filelist
Where ownername is the new owner, and filelist is the list of
files to change. You must own the file which your are goin to
change, unless you are a superuser....then u can change ANYTHING!
chgrp is a similar command which will change the group
ownership on a file. If you are going to do both a chown and a
chgrp on a file, then make sure you do the chgrp first! Once the
file is owned by someone else, you cant change nything about it!
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Sometimes just seeing who is on the system is a challenge in
itself. The best way is to write your own version of who in C,
but if you can't do that then this may be of some help to you:
who followed by on or more of the following flags:
-b Displays time sys as last booted.
-H Precedes output with header.
-l Lists lines waiting for users to logon.
-q displays number of users logged on.
-t displays time sys clock was last changed.
-T displays the state field (a + indicates it is
possible to send to terminal, a - means u cannot)
-u Give a complete listing of those logged on.
**who -HTu is about the best choice for the average user**
##by the way, the list of users logged on is kept in the file
/etc/utmp. If you want to write your own personalised version of
who in C, you now know where to look!###
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When a users state field (see -T flag option for who
command) says that a user has their message function on, this
actually means that it is possible to get stuff onto their
screen.
Basically, every terminal on the system has a file
corresponding to it. These files can be found in the /dev
directory. You can to anything to these files, so long as you
have access -eg you can read them, and write to them, but you
will notice that they never change in size. They are called
character specific files, and are really the link between the
system and the terminals. Whatever you put in these files will
go staright to the terminal it corresponds to.
Unfortunately, on most systems, when the user logs in, the
"mesg n" command is issued which turns off write access to that
terminal, BUT- if you can start cating to that terminal before
system issues the mesg n command, then you will continue to be
able to get stuff up on that terminal! This has many varied uses.
Check out the terminal, or terminal software being used.
Often you will be able to remotely program another users
terminal, simply by 'cating' a string to a users screen. You
might be able to set up a buffer, capturing all that is typed, or
you may be able to send the terminal into a frenzy- (sometimes a
user will walk away without realizing that they are sill
effectively logged on, leaving you with access to their
account!). Some terminal types also have this great command
called transmit screen. It transmits everything on the screen,
just as if the user had typed it !
So just say I wanted to log off a user, then I would send a
clear screen command (usually ctrl l), followed by "exit"
followed by a carriage return, followed by the transmit screen
code. Using ths technique you can wipe peoples directories or
anything. My favourite is to set open access on all their files
and directories so I can peruse them for deletion etc at my own
leisure).
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If you ever briefly get access to another persons account
eg. they leave the room to go to toilet or whatever, then simply
type the following:
chmod 777 $HOME
chmod 777 $MAIL
Then clear the screen so they dont see what you just typed.
Now you can go look at their directory, and their mail, and
you can even put mail in their mail file. (just use the same
format as any mail that is already there!). Next time they log in
the system will automatically inform them they have new mail!
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Another way to send fake mail to people is to use the mail
server. This method produces mail that is slightly different to
normal, so anyone who uses UNIX a bit may be suspiscious when
they receive it, but it will fool the average dumb fuck user!
type telnet
the following prompt will appear:
telnet>
now type :
open localhost 25
some crap will come up about the mail server..now type:
mail from: xxxxxx Put any name you want.
some more bullshit will come up. Now type:
rcpt to: xxxxxx Put the name of the person to receive mail here.
now type:
data
now you can type the letter...end it with a "."
type quit to exit once you are done.
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Heres one for any experimenters out there...
It is possible to create files which simply cannot be deleted
from the standard shell. To do this you will have to physically
CREATE THE FILE USING A C PROGRAM or SCRIPT FILE, and you will
have to use a sequence of control characters which cannot be
typed from the shell. Try things like Ctrl-h (this is the
code for the delete key). Just a file with the name Ctrl-h would
not be deleteable from the shell, unless you used wildcards. So,
make it a nice long series of characters, so that to delete the
file, the user has no choice but to individually copy all his
files elsewhere, then delete everything in his directory, and
then copy all his files back.....this is one of my
favourites..gets em every time!
The following script file is an example which will create a
file with the name Ctrl-h. You MUST tyoe this file in using the
vi editor or similar.
*****If you are not very good with vi, type "man vi" and print the
help file...it even contains stuff that I find useful now and
then.*****
type the following in vi...
echo'' > 'a^h'
***NOTE...to get the ^h (this really means ctrl-h) from vi type:
Ctrl v
Ctrl h
The Ctrl v instrcts vi to take the next character as a ascii
character, and not to interpret it.
change the access on the file you just created and now
execute it. It will create a file which looks like it is called
a, but try to delete it !..use wildcards if you really want to
delete it.
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