GUIDE TO (mostly) HARMLESS HACKING
Vol. 2 Number 2
Linux!
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Unix has become the primo operating system of the Internet. In fact,
Unix is the most widely used operating system in the world among computers
with more power than PCs.
True, Windows NT is coming up fast as a common Internet operating system,
and is sooo wonderfully buggy that it looks like it could become
the number one favorite to crack into. But today Unix in all its wonderful
flavors still is the operating system to know in order to be a truly
elite hacker.
So far we have assumed that you have been hacking using a shell account
that you get through your Internet Service Provider (ISP). A shell account
allows you to give Unix commands on one of your ISP's computers. But you
don't need to depend on your ISP for a machine that lets you play with
Unix. You can run Unix on your own computer and with a SLIP or PPP connection
be directly connected to the Internet.
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Newbie note: Serial Line Internet Protocol (SLIP) and Point-to-Point
Protocol (PPP) connections give you a temporary Internet Protocol (IP)
address that allows you to be hooked directly to the Internet. You have
to use either SLIP or PPP connections to get to use a Web browser that
gives you pictures instead on text only. So if you can see pictures on
the Web, you already have one of these available to you.
The advantage of using one of these direct connections for your hacking
activities is that you will not leave behind a shell log file for your
ISP's sysadmin to pore over. Even if you are not breaking the law, a shell
log file that shows you doing lots of hacker stuph can be enough for some
sysadmins to summarily close your account.
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What is the best kind of computer to run Unix on? Unless you are a wealthy
hacker who thinks nothing of buying a Sun SPARC workstation, you'll probably
do best with some sort of PC. There are almost countless variants of Unix
that run on PCs, and a few for Macs. Most of them are free for download,
or inexpensively available on CD-ROMs.
The three most common variations of Unix that run on PCs are Sun's Solaris,
FreeBSD and Linux. Solaris costs around $700. Enough said. FreeBSD is really,
really good. But you con't find many manuals or newsgroups that cover FreeBSD.
(Note: nowadays you can get Solaris for about
$15 if you sign
up as a Solaris developer.)
Linux, however, has the advantage of being available in many variants
(so you can have fun mixing and matching programs from different Linux
offerings). Most importantly, Linux is supported by many manuals, news
groups, mail lists and Web sites. If you have hacker friends in your area,
most of them probably use Linux and can help you out.
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Historical note: Linux was created in 1991 by a group led by Linus
Torvalds of the University of Helsinki. Linux is copyrighted under
the GNU General Public License. Under this agreement, Linux may be redistributed
to anyone along with the source code. Anyone can sell any variant of Linux
and modify it and repackage it. But even if someone modifies the source
code he or she may not claim copyright for anything created from Linux.
Anyone who sells a modified version of Linux must provide source code to
the buyers and allow them to reuse it in their commercial products without
charging licensing fees. This arrangement is known as a "copyleft."
Under this arrangement the original creators of Linux receive no licensing
or shareware fees. Linus Torvalds and the many others who have contributed
to Linux have done so from the joy of programming and a sense of community
with all of us who will hopefully use Linux in the spirit of good guy hacking.
Viva Linux! Viva Torvalds!
**********************
Linux consists of the operating system itself (called the "kernel")
plus a set of associated programs.
The kernel, like all types of Unix, is a multitasking, multi-user operating
system. Although it uses a different file structure, and hence is not directly
compatible with DOS and Windows, it is so flexible that many DOS and Windows
programs can be run while in Linux. So a power user will probably want
to boot up in Linux and then be able to run DOS and Windows programs from
Linux.
Associated programs that come with most Linux distributions may include:
* a shell program (Bourne Again Shell -- BASH -- is most common);
* compilers for programming languages such as Fortran-77 (my favorite!),
C, C++, Pascal, LISP, Modula-2, Ada, Basic (the best language for a beginner),
and Smalltalk.;
* X (sometimes called X-windows), a graphical user interface
* utility programs such as the email reader Pine (my favorite) and
Elm
Top ten reasons to install Linux on your PC:
1.When Linux is outlawed, only outlaws will own Linux.
2. When installing Linux, it is so much fun to run fdisk without backing
up first.
3.The flames you get from asking questions on Linux newsgroups are
of a higher quality than the flames you get for posting to alt.sex.bestiality.
4.No matter what flavor of Linux you install, you'll find out tomorrow
there was a far more 3l1te ersion you should have gotten instead.
5.People who use Free BSD or Solaris will not make fun of you. They
will offer their sympathy instead.
6.At the next Def Con you'll be able to say stuph like "so then I su-ed
to his account and grepped all his files for 'kissyface'." Oops,
grepping other people's files is a no-no, forget I ever suggested it.
7.Port surf in privacy.
8.One word: exploits.
9.Installing Linux on your office PC is like being a postal worker
and bringing an Uzi to work.
10.But - - if you install Linux on your office computer, you
boss won't have a clue what that means.
What types of Linux work best? It depends on what you really want. Redhat
Linux is famed for being the easiest to install. The Walnut Creek Linux
3.0 CD-ROM set is also really easy to install -- for Linux, that is! My
approach has been to get lots of Linux versions and mix and match the best
from each distribution.
I like the Walnut Creek version best because with my brand X hardware,
its autodetection feature was a life-saver.
INSTALLING LINUX is not for the faint of heart! Several tips for surviving
installation are:
1) Although you in theory can run Linux on a 286 with 4 MB RAM and two
floppy drives, it is *much* easier with a 486 or above with 8 MB RAM, a
CD-ROM, and at least 200 MB free hard disk space.
(Note: Nowadays you need at least a 386,
and will do much better with a 486 or better, at least 12 MB memory, bootable
from the CD-ROM, and at least 500G free hard drive space.)
2) Know as much as possible about what type of mother board, modem,
hard disk, CD-ROM, and video card you have. If you have any documentation
for these, have them on hand to reference during installation.
3) It works better to use hardware that is name-brand and somewhat out-of-date
on your computer. Because Linux is freeware, it doesn't offer device drivers
for all the latest hardware. And if your hardware is like mine -- lots
of Brand X and El Cheapo stuph, you can take a long time experimenting
with what drivers will work.
4) Before beginning installation, back up your hard disk(s)! In theory
you can install Linux without harming your DOS/Windows files. But we are
all human, especially if following the advice of point 7).
5) Get more than one Linux distribution. The first time I successfully
installed Linux, I finally hit on something that worked by using the boot
disk from one distribution with the CD-ROM for another. In any case, each
Linux distribution had different utility programs, operating system emulators,
compilers and more. Add them all to your system and you will be set up
to become beyond elite.
6) Buy a book or two or three on Linux. I didn't like any of them! But
they are better than nothing. Most books on Linux come with one or two
CD-ROMs that can be used to install Linux. But I found that what was in
the books did not exactly coincide with what was on the CD-ROMs.
7) I recommend drinking while installing. It may not make debugging
go any faster, but at least you won't care how hard it is.
Now I can almost guarantee that even following all these 6 pieces of
advice, you will still have problems installing Linux. Oh, do I have 7
advisories up there? Forget number 7. But be of good cheer. Since everyone
else also suffers mightily when installing and using Linux, the Internet
has an incredible wealth of resources for the Linux -challenged.
If you are allergic to getting flamed, you can start out with Linux
support Web sites.
The best I have found is http://sunsite.unc.edu:/pub/Linux/. It includes
the Linux Frequently Asked Questions list (FAQ), available from
sunsite.unc.edu:/pub/Linux/docs/FAQ.
In the directory /pub/Linux/docs on sunsite.unc.edu you'll find a number
of other documents about Linux, including the Linux INFO-SHEET and META-FAQ,
The Linux HOWTO archive is on the sunsite.unc.edu Web site at: /pub/Linux/docs/HOWTO.
The directory /pub/Linux/docs/LDP contains the current set of LDP manuals.
You can get ``Linux Installation and Getting Started'' from sunsite.unc.edu
in /pub/Linux/docs/LDP/install-guide. The README file there
describes how you can order a printed copy of the book of the same
name (about 180 pages).
Now if you don't mind getting flamed, you may want to post questions
to the amazing number of Usenet news groups that cover Linux. These include:
comp.os.linux.advocacy
Benefits of Linux compared
comp.os.linux.development.system
Linux kernels, device drivers
comp.os.linux.x
Linux X Window System servers
comp.os.linux.development.apps
Writing Linux applications
comp.os.linux.hardware
Hardware compatibility
comp.os.linux.setup
Linux installation
comp.os.linux.networking
Networking and communications
comp.os.linux.answers
FAQs, How-To's, READMEs, etc.
linux.redhat.misc
alt.os.linux
Use comp.os.linux.* instead
alt.uu.comp.os.linux.questions
Usenet University helps you
comp.os.linux.announce
Announcements important to Linux
comp.os.linux.misc
Linux-specific topics
Want your Linux free? Tobin Fricke has pointed out that "free copies
of Linux CD-ROMs are available the Linux Support & CD Givaway web site
at http://emile.math.ucsb.edu:8000/giveaway.html. This is a project where
people donate Linux CD's that they don't need any more. The project was
seeded by Linux Systems Labs, who donated 800 Linux CDs initially!
Please remember to donate your Linux CD's when you are done with them.
If you live near a computer swap meet, Fry's, Microcenter, or other such
place, look for Linux CD's there. They are usually under $20, which
is an excellent investment. I personally like the Linux Developer's
Resource by Infomagic, which is now up to a seven CD set, I believe, which
includes all major Linux distributions (Slackware, Redhat, Debian, Linux
for DEC Alpha to name a few)plus mirrors of tsx11.mit.edu and sunsite.unc.edu/pub/linux
plus much more. You should also visit the WONDERFUL linux page at
http://sunsite.unc.edu/linux, which has tons of information, as well
as the
http://www.linux.org/. You might also want to check out
http://www.redhat.com/ and http://www.caldera.com/ for more
information on commercial versions of linux (which are still freely
available under GNU)."
How about Linux security? Yes, Linux, like every operating system, is
imperfect. Eminently hackable, if you really want to know. So if you want
to find out how to secure your Linux system, or if you should come across
one of the many ISPs that use Linux and want to go exploring (oops, forget
I
wrote that), here's where you can go for info:
ftp://info.cert.org/pub/cert_advisories/CA-94:01.network.monitoring.attacks
ftp://info.cert.org/pub/tech_tips/root_compromise
http://bach.cis.temple.edu/linux/linux-security/
http://www.geek-girl.com/bugtraq/
There is also help for Linux users on Internet Relay Chat (IRC). Ben
([email protected])
hosts a channel called #LinuxHelp on the Undernet IRC server.
Last but not least, if you want to ask Linux questions on the Happy
Hacker list, you're welcome. We may be the blind leading the blind, but
what
the heck!
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Copyright 1996 Carolyn P. Meinel. You may forward the GUIDE TO (mostly)
HARMLESS HACKING as long as you leave this notice at the end.
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