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- UNIX Abuse Collection
- Written By ZeeBee Australia Jan 1990
-
-
- Ok Hacksters...we all know the importance of a good
- understanding of the UNIX V operating system, but I find that
- just an understanding alone is quite simply not enough.
-
- Our little articles are not intended for those wishing to
- gain an understanding of the UNIX environment. Instead, we aim
- to show you how to truly ABUSE the UNIX system to it's fullest
- potential.(And lets face it, UNIX really does have some really
- great abusable features!)..so....grab your UNIX accounts and
- passwords, and lets go!
-
-
- **UNIX ABUSE COLLECTION PART 01**
- ****INVISIBILITY AND COVER UP TECHNIQUES***
-
- One thing that really used to bug me about using a UNIX
- system was that I always felt like someone was watching me. It's
- just too easy to see what other users are doing, and as soon as
- you discover something good, everyone else sees what you are
- doing, and VOOM!...there goes your big secret. System operators
- too, can easily pinpoint just who is stuffing around with their
- system simply by seeing what processes are running under your
- name. So, I set out to find ways around this.
-
- One way to cover up what you are doing is to find and copy
- the command that you wish to perform. As an example, just say I
- want to cat a whole load of bullshit to someones terminal, but I
- dont want anyone to see that I am executing the cat command.
- First of all I find the cat command. On most systems it will be
- somewhere in the /bin directory. Once you have found the command
- you must copy it (if possible) to your own directory and rename
- it to something inconspicuous. Most commands can be found
- somewhere in the /bin or /usr/bin directories, but if you cant
- find them, just look at your path list and see where UNIX is
- looking for them. (typing echo $PATH is one way to view your path
- list.)
- Keep it in mind that not all commands are copyable (do an ls
- -al and look at the access flags to see if they are) if the
- access flags have an 'r' in the column 3rd from the far right,
- then you can read it, ie copy it !
- One advantage to this technique is that if you find a bug
- with a certain command, you have a copy of the faulty code, so
- even if the computer staff fix the bug, you will have the old
- version ! Neat !
-
- BUT! Don't worry if you can't copy the file! The following
- technique will do just the same job, without the need to copy the
- file. To do this you will need to write a program in C, compile
- it, and place it somewhere where it is safe for you to call
- whenever you want.
-
-
- This is the small, and usefull piece of code:
-
- main()
- {
- execl("/bin/ls","a.out","-l",(char *)0);
- }
-
-
- The above piece of code will execute the ls -l command, but
- will generally show up as a.out -l whenever someone has a look at
- what you are doing!
- The "/bin/ls" is the path of the 'ls' command. Put the path
- of any program you wish to execute here.
- The "a.out" is what anyone else will think you are running.
- Put anything you want here. The command doesnt even have to
- exist!
- The "-l" is the flag being passed to the ls command. You
- cant cover up flags which are passed. Damn!
-
-
- So, by using this, you can run any program with execute
- access and make it look like you are running something else. You
- could even put in a whole path where I put the "a.out" and
- really confuse the shit out of people when they go looking for
- this great program you are running.
-
- While we are on the topic, I would just like to stress the
- importance of continually checking to see what others on the
- system are doing. I find the "w -d" "ps -fu USERNAME" and "ps -
- fa" commands to be most usefull at this. On one system I was
- actually able to see system operators creating new accounts, and
- the account names and passwords were being passed. So one of the
- processes being executed by some priveleged user looked like
- this:
-
- megauser 273 10:00:12 createaccount john zephyr ;
-
- * In the above example, john is the account name, zephyr is the
- password.*
-
- We got about 100 accounts that day !
-
- And remember, as soon as any new toy is installed on the
- system, somebody will be using it, so just keep an eye on them to
- see what they do.
-
-