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Happy Hacker Digest April April 29-30, 1997

      This is a moderated list for discussions of *legal* hacking.
                        Moderator is Matt Hinze

             Send posts to: matt@cs.utexas.edu (Matt Hinze)
           [if you can, include a "HH" in the subject header]

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          The Happy Hacker Digest Webpage, located at
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          discussed web sites and past URLs Of The Day
            (usually updated the day after the Digest is released).

         H a p p y  H a c k i n g !


Table Of Contents

* Note From Matt
* pwd.db File?
* Programming Languages
* Windows Telnet Daemon
* Shell Account
* For Further Reading...
* HyperTerminal
* fg And bg
* Miscellany
* Cyberspace Shell Account
* Rental Car GPS
* Covering Your Tracks
* Phreaking In Oz
* Accessing That Darned shadow File
* List Demographics
* Working With Security Consultants


*** Note From Matt

I'm sorry that this digest took so long to send out - it's the last
week of classes here at The University of Texas. I've been swamped.
Keep an eye out for a lot of changes to the Happy Hacker Webpage and
the Digest next week, I have a lot of ideas, but most of them take
some time to implement.

So continue to send your posts, suggestions, and nominees for URL Of
The Day to me, at matt@cs.utexas.edu Thanks!


*** pwd.db File?

From: Tom Mucha <tmucha@usa.net>


I was FTP-ing around one day and I stumbled across a "pwd.db" file.
What is this file?  It's 40KB, and when I try to view it with a text
editor, it's only odd looking characters.  If this is a password file,
what would I use to view it?  I thought "passwd" files were the only
password files. Is it crackable?

Thanks for any help, keep up the good work!

Tom Mucha

*** Programming Languages

From: Jason Terwilliger <jterwill@hotliquid.com>

I got a question. It's generally agreed that C++ is the language of
choice for hacking. I was wondering if anyone had opionions on other
languages. In particular, I was interested if anyone had an opinion on
how appropriate JAVA was since that's the only other major
Object-Oriented language around that I'm familiar with (besides
Eiffel). Thanks!


                           Do I believe in the bible?
                           Hell man, I've seen one!!

[Matt: Well, it's *not* generally agreed that C++ is the best language
for hacking. I think it's up there, though. Among the best are Perl
and C (csh and tcsh included). I haven't been too impressed with Java
thusfar. Most of the Java applets or applications I've seen have been
used cosmetically. I wouldn't make learning it a priority. You should
look into Haskell for *nix. It's object-oriented, but functional (as
opposed to languages like C++ and Pascal, which are imperitive), so
learning it might be difficult, especially if you have an imperitive
background. Check out comp.lang.functional for more info about
functional programming.]

*** Windows Telnet Daemon
From: "Mr. Snoid" <snoid@geocities.com>

> This touches on a  topic about which I've been very curious;  I
> would like to expand on it.  Could deviant's friends telnet into his
> box if he had a dialup account, and, therefore, a
> dynamically-assigned IP?  Assuming, of course, that he was using one
> of the little find-your-dynamic-ip progs and could relate it to them
> during the session.  In a sideways-related vein, could one telnet
> (or otherwise gain access remotely) into a Windows box?  Exactly how
> do Windows' ports work, in comparison to UNIX ports?

I found a telnet daemon for Windows 3.1 called WinTD.
You can set to listen on the default telnet port (23) or any other
port. It allows someone who is logged in to your machine to look
around your harddrive, read files, and even "exec" or "kill" programs
running on your computer (if they have the right command privileges
that is) The daemon is "freeware" but the help file costs $10.
(sheesh) I'm not sure where I found it; it was either TUCOWS
or Stroud's

Mr. Snoid

*** Shell Account

From: me <umeatoug@cc.UManitoba.CA>

just wondering, is every directory on my shell account that I can "cd"

myself into legal to acs? will going into any directories cause the
sysadmins to cancel my account?


[Matt: If you have access to a directory, it's legal to 'cd' into it.]

*** SUID?

From: Warpy <warpy@null.net>

>What's the big deal with suid?  I know what it means, but I don't see
>how this could be used to gain root.  If a suid program crashes, it
>terminates itself, right?  Or is there a way to get to a prompt from

>From my limited understanding (and a great article by Aleph1), suid
root programs are a problem. Suid itself stands for (S)et-(U)ser-(ID),
which means at some stage in the programs operation, a suid root
program is operating at root.

The recent spate of buffer overflow programs exploit this. What these
buffer overflow exploits actually do, is "exploit" poor coding in the
programs being overflowed. These programs do not "check bounds" which
allow someone to stuff more data into a buffer than the program can
handle. These buffer overflows allow someone to change the return
address of a function, this way someone can possibly get the program
to execute arbitrary commands - such as /bin/sh, and if the program is
suid root then you have now got a root shell.

If I have fuxored up the explanation feel free to correct me, or
better yet if you still have questions why not read article 14, in
Phrack 49.


A great hack is accomplished before it has begun...
(paraphrased from Sun Tzu)   -[warpy@null.net]-

*** For Further Reading ...

From: Jason Terwilliger <jterwill@hotliquid.com>


The series on Shell Accounts is excellent. One suggestion though is on
books for newbies on UNIX. Though "UNIX in a Nutshell" is an excellent
reference..it's definately not an easily understood thing for people
unfamiliar with the system. (the author even states in the intro that
it's not meant to be a tutorial) To give a new person a good solid
knowledge of beginning UNIX, I'd like to suggest two books:

UNIX in 7 Days" by Dave Taylor (SAMS): Gives lots of examples and is a
good step by step tutorial for those new to UNIX. Teaches you pretty
much everything you need to know for basic knowledge in getting

"A Student Guide to UNIX" by Harley Hahn (McGraw-Hill): I think this
is the most reccomended book around for novices..Cover everything the
other book does, but doesn't give it to you like a tutorial-based

Just wanted to give my 2cents worth, hope this helps:)


                           Do I believe in the bible?
                           Hell man, I've seen one!!

*** HyperTerminal

From: WaXbOaRd <ak1128@onslowonline.net>

me again (and again and again...)

Ok, In the GTMHH 1.1 you said that win95 has a Terminal Emulation
Program (vt 100) included in the access. program.   Is that the
HyperTerminal proggie?  If it is, when i log on to my ISP, it gives

[Matt: You might be thinking of TELNET.EXE.]

welcome to onlsowonline
user name:

when i type all the appropriate stuph, all that comes on is a series
of ^H^H^H^H^H^H^H^H^H^087888^H^H^H (which scrolls down about 5 pages)
then it boots me off.  Am i doing something wrong?  I'm trying to find
some info on a person and everytime i try something i run into a

[Carolyn: Your ISP is trying to set up a PPP connection with
Hyperterminal. All I can say is complain to tech support. I've never
had any luck with tech support when that happens with my ISPs.  But
sometimes Hyperterminal will successfully set up a connection to your
shell account, and sometimes all you get is a failed PPP connection
attempt. Solution: use a better program, for example Ewan, which is
free. You may download it from the /utils directory at
obscure.sekurity.org, courtesy of jericho.]

*** fg And bg

From: Xenakis <xenakis@epix.net>

>'^C' (interrupt) will stop a process that you are currently
>running, and '^Z' (suspend) will (often) suspend a process which you
>can later re-start with the fg command (this is often handy when you
>get a talk-req while you are in the middle of doing something really
>important and you don't want to lose your place)

With doing ^Z, fg will run the program in the ForeGround, and bg will
run the program in the BackGround....
(I believe that you meant bg instead  ;)

-Xenakis xenakis@epix.net

*** Miscellany
From: jericho@dimensional.com

> (I have read all the phreaker's box specs and they look like so
> much fun!! I want to try them all, but will they work in Oz??
> I know they obviously do with ol' ma bell's phone system...

Actually, 90% of the box plans out there never did work on any phone


> However, I wanted to correct several problems with the guide.  First
> of all, in your file permissions tutorial (which incidently neglects
> the arguably important information of HOW to CHANGE them), you write:
> >If you were to someday discover your permissions looking like:
> >
> >       drwx--xrwx      newbie user     512 Apr 22 17:36 www/
> >
> >Whoa, that ^r^ in the third place from last would mean anyone can hack
> >your Web page!
> This is not correct.  AFAIK, every UNIX variant has exclusive
> permissions. In the example above, you have DENIED read and write
> permission to everyone in the "user" group.  This this person:

That should have been talking about the last 'w', and both of you are
wrong I think :)  The last 'w' shows "other" write access. That means
anyone on the system can write to that file. Even if someone is in
your group, I think on most systems they will also fall under "other"
and be able to write that way.

> would NOT be able to tamper with your files.  Presumably most users on
> the system would fit this description.  Thus it is not correct that
> "anyone can hack your Web page!".

"anyone" because the last 'w'.

> Also you claim that "Jericho is a security consultant runs his own
> Internet host, obscure.security.org".  If you had used those 31337
> haxx0r T00lz 'nslookup' and 'whois' which you always talk about, you
> would have found that the host doesn't exist, and the domain is run by
> Marc Tobias. I think you mean "sekurity.org".

sekurity.org is the correct spelling.

*** Cyberspace Shell Account

From: LGPryor@worldnet.att.net


On your Mon, April 28, 1997 issue you had "Free Shell Account" listed
on your table of contents. I checked it out, and it's nothing big. You
can't access anything off of the Account Provider's system unless you
pay them $6 a month and give them proof of a valid ID. If you're into
chatting and BBS stuff, then you should check it out. With the free
account you don't even have to give your real name. But for hackers,
this ain't the thing.

That's it. Todo es amor, adios.
Wayfarer X

[Matt: Right. It's not very useful, but it is a shell (with compilers
;> ) nonetheless.]

*** Rental Car GPS

From: [anonymous]

This is a response to Hacking Rental Car GPS for the Happy Hacker
mailing list.  If you decide to post it, please make it anonymous.

> On the back of the console ( the part that is in the front of the car)
> there is a small serial port plug thing with no label or anything but
> It can be easily removed...and plugged into something else...say a
> laptop..But I don't have much experience with this kind of stuff and I
> was wondering if anyone out there has ever tried to hack one of these,
> or if it is even possible??

The presence of a serial cable implies at least two devices, one the
display/console/computer and at the other end a GPS
receiver/processor. The GPS probably sends data to the console as NMEA
(National Marine Electronics Association) sentences.  These sentences
include all kinds of locational data including lat, long, elevation,
time etc. You should be able to find definitions on the web somewhere.
I think the standard transmission is 4800BPS/8/N/1.  To check this
out, connect the serial cable to your laptop and run a terminal
emulator with those settings on the serial port.  You should see some
sort of formated data.  It is also ossible that Hertz is keeping track
of more than just GPS data.  If you do get identifiable GPS data,
check to see if there is anything else that does not fit GPS
parameters.  If there is, take some samples, post them here and lets
see what we can make of them.  If you don't get any data, try
switching pins 2 and 3 (you might be trying to receive on the
transmit pin). If you get garbage, change the comms settings.

Going in the other direction, connect a serial cable up to your laptop
and the console unit.  If it just receives and displays the GPS data,
you should not see anything.  If you get any kind of activity in your
terminal emulator, it possibly (wild speculation here) means that the
computer is polling several different devices for input or is storing
data to a third device (a hidden hard disk perhaps?).  If this happens
you might try sending some control characters at the computer
something might throw it into command mode (after all, Hertz has to
have a way of servicing the unit right?).  If you get the response
"OK" to something you type, you probably hit the jackpot!

If it were me, I wouldn't put a computer in a car just for the
convenience of the driver, I'd use it to double check mileage and
otherwise keep track of the car and its use (max speed time at
location, hours of travel etc.).  Lets hear from the truely paranoid
here, what can Hertz learn about these travelers just by logging trip
data in an on-board computer???

[Matt: Ooo, interesting. I'm in rental cars all the time - next time
I'll bring my laptop. :) ]

*** Covering Your Tracks

From: n-treeg@ix.netcom.com

>Ok i have a question...I know your probaly really busy so answer this
>as soon as you can. Well with my ISP i use it gives me a domain
>name..and i see this as Not good and a problem...Becasue whenever i
>connnect to a remote computer..in the logs or whatever it will say
>logged in "my domain name" and if my domain name is logged on abunch
>of computer systems i will get cought right? And if this is true is
>there a way to get rid of or hide my domain name? And if this is not a
>problem please say so...I would love any info u can give me on this
>[Matt: I'm assuming (since this is a digest about legal hacking) that
>it won't be problem. Everything you're doing is legal, right? ;> ]

In the event that you may have cracked a password or two and have
actually logged on to these sytems, you may want to cover your tracks.
A simple method that will make you a little less obvious to the
casual, average user is to telnet, open localhost  after you've logged
in so that they won't see your IP in the "last login from: etc...
etc..." blurb the next time the legitimate user logs in.  This won't
hide you from a who and it won't remove your presences from the logs.
For info on how to do this you can peruse
http://www.geocities.com/CapeCanaveral/3498/cover1.htm for a tutorial
on covering your tracks.  [NOTE: Must be root to edit those files.  In

addition, if you are discovered, editing files will most certainly put
you in hot water with the sysadmins. IMPORTANT: NEVER DELETE SYSTEM
FILES.]  Do no damage and hopefully no damage will come to you. I hope
you gain some knowledge and insight from that web page.  Be good now!

*** Phreaking in Oz

From: Warpy <warpy@null.net>

Hrmm Phreaking in Oz, once thought a dying age..

Alright, I'm going to go thru the various forms of phreaking which are
applicable in Oz (as far as I know) and some sites you "might" be able
to find further info.

Ok, the number one Oz phreaks tool is the beige box. These simply
connect you phone to a phone line via alligator clips. However, that
phone line could either be in your own house.. or down the road in
some telstra pit.

Redboxes do NOT work. How do I know? Next time you're at a payphone
and put in some coins. Do you hear any tones? Nope.

Blue Boxes. I would hope that the majority of you realise that they
(for the larger part) do NOT work. However if you can manage to call
some third world country, it is often possible to blue box of them as
their switching technology is often ancient. The problem is the cost
of the call to the third world country. Can anyone say "1800"? ;)

Hrmm what other boxes are there...

There is the black box, which makes it so the caller doesn't have to
pay for their call. However now that i think about it, it probably
works, but as most calls get timed out within a certain period of
time, it may not work for long.

Now on to some general info about phreaking in Australia. It is a very
secret art. Literally. The reason American phreaking techniques still
work years after how to do them have been published is due to the
makeup of the US telecommunications industry, and the costs involved
of replacing existing telecommunication networks. HOWEVER. In
Australia up until recently Telstra (formerly known as Telecom
Australia and OTC) was the sole provider of telecommunications. This
meant that they could upgrade the ENTIRE system around the country
when these faults are discovered, not just small pockets (which is
what happens in the US). Hence any knew phreaking knowledge and/or
techniques are limited to a select few to prevent Telstra getting wind
of it.

One example occured when I was at the movies one day. I was walking
past a bunch of teenagers at the payphone (around 13/14 years old)
playing with the keypad. After they walked off I looked at the phone
display. "PHONE OUT OF SERVICE". Now I had seen this done once before
by a friend of mine, but whereas he did a similar "hack" which lasted
only about three minutes, these kids must've done the permanent one
which required a Telstra service dude to come out and reset it. I had
not personally read about how you can do this, but these kids had. And
I had one guess where they got it from. A bulletin board.

Needless to say this kind of childish behaviour is the EXACT thing
which causes the phone system to be patched, and once again be reduced
to beige boxing from your local telstra pit.

Oz Phreaking Resources: Look up an emag called Neurocactus, you will
either find it on local boards, or there is a site on the net
somewhere. Very good info for the beginning Aussie phreak.

That's about it, if you find anything of interest please feel free to
email me..


A great hack is accomplished before it has begun...
(paraphrased from Sun Tzu)   -[warpy@null.net]-

[Matt: Note: Stealing phone calls is illegal.]

*** Accessing That Darned shadow File

From: "Joe Rowe" <Joe.Rowe@btinternet.com>

Help!, i am having troubles with accessing the shadow password file on
my college UNIX system (any system for a matter of fact). There is a
small program that makes use of getpwent() however this get entries
from the passwd file and not the shadow file, i edited it to use
getspwent() or whatever (the shadow equiverlent) which of course
denies access. In text's it mentions that successive calls to
getpwent() have to be made, are they just refering the the while no
more entries loop (which brings up a big *0*) or do you have to try
this many times ? I would like to now of any exploits or methods of
aquiring the contents of the shadow pword file a) on a local system
without using browser exploit or b) without using the phf exploit.
Also i enquired to my lecturer could i read directly from the file
systems/HD for the contents of the shadow pword file, he says NO, is
this correct is or their a way ?? :-( if not, surely systems closed to
exploits are secure :-(

NB : I have about 3 years of 'C' experience so im not that thick :-)


has any one got a..
 Port Scanner,
 IP/Packet sniffer.
if they have or know of the location of a *good* *working* one(s)
could you
let me know (please...)

[Matt: Do a web search, and scan through the past URLs Of The Day.]


*** List Demographics

From: "Carolyn P. Meinel" <>

A search for country domain names (which is an undercount, since many
people have email addresses that don't include their country's ISO
domain code) reveals:

United Kingdom..50

Total subscribers as of 4/29/97 = 3,631

[Matt: This will interest everyone, especially the journalists and law
enforcement officials subscribed to the list.]

*** Working With Security Consultants
From: Warpy <warpy@null.net>

This is just a short note to newbies. Recently I emailed a local
security consultant about doing work experience with him. I had spoken
to him via email a couple of times previously, and to my shock and
delight he was open to the idea.

So if any of you guys are SERIOUS about getting into computer security
work, and have more than an ounce of experience, I suggest you contact
your nearest computer security firm and enquire about possibly doing
some work experience for them (make sure you mention the word FREE).

Good luck,


A great hack is accomplished before it has begun...
(paraphrased from Sun Tzu)   -[warpy@null.net]-


Matt Hinze <matt@cs.utexas.edu>

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