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March 9, 1998

URL of the week: (http://www.pcweek.com/) You'll see why as you read on!
See back issues if the Happy Hacker Digest and Guides to (mostly) Harmless
Hacking at http://cmeinel.com/happyhacker.html.
Super Swedish Happy Hacker site: http://w1.340.telia.com/~u34002171/hhd.html.
Coming soon: Spanish translations of the Digests!
GTMHH en espanol: http://underhack.islatortuga.com
Table of Contents:

* Ziff Davis helps with anonymous email
* Hoaxes - Learn to open your eyes, ask questions and think
* Digest Q- IP Spoof; Tete-a-tete; Line Install
* Firewall walkarounds

*** Ziff Davis helps with anonymous email -- RJ
Ssshhh!! Don't let anyone know that you found this out. But Ziff Davis has
decided to let anyone who wants to have some "harmless" fun use their web
server to do it -- and to do it totally anonymously!

I first found this out since I subscribe to ZD's "PC Week Inbox Direct".
Each week ZD sends out an email with an HTML attachment that links to
stories on their PC Week site. A couple of weeks ago I noticed an
interesting new "feature" had been added to their repertoire of services --
the ability to email the article which you were looking at to the person of
your choice. When I clicked on the "email this story" button, I was
presented with a screen which asked me to answer four simple questions:

1--"Send To:"
2--"Your email:"
4--Select the message format -- text or HTML

"Now", I thought to myself, "surely you can't just put ANY OLD EMAIL
ADDRESS as your own and have the message headers reflect that information!
Or can you ??" Well, as it turns out -- you can!!! I gave Carolyn a heads
up on my suspicions, and then sent her a message which claimed to be from a
certain well known US politician who has problems with his zipper. She
found no way of tracing who it had come from, other than the stated sender.
Then I sent myself a message which looked as though it came from one of my
friends at WC3. ("WC3" is one of many White Collar Crime units at the
FBI). Here it is, headers and all, for your review:
Received: from u2.zdnet.com.
by mail.rapidsite.net (8.8.5/8.8.5) with SMTP id LAA03680
for <>; Wed, 21 Jan 1998 11:06:40 -0500 (EST)
Received: by u2.zdnet.com. (SMI-8.6/SMI-SVR4)
id LAA24833; Wed, 21 Jan 1998 11:06:40 -0500
Date: Wed, 21 Jan 1998 11:06:40 -0500
Message-Id: <199801211606.LAA24833@u2.zdnet.com.>From: WC3@fbi.gov
To: Subject: FWD: PC WEEK: Serious E-commerce sites will find Kiva a must-buy
Content-Type: text

This message was forwarded to you from ZDNet (http://www.zdnet.com) by

Comment from sender:
look close

&lt<The article followed here&gt>~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
You'll notice there is nothing in the headers which indicates the actual
address of the sender, only the address I chose to type in.

Imagine all of the fun you could have with this! For instance, a person
may take one of the Monica Lewinsky articles which has appeared in PC Week,
and forward it to "news@cnn.org" from "president@whitehouse.gov" and in the
"Comment" field say something like: "I'm tired of all of the bad press,
especially articles like the one I've forwarded with this message. I knew
you folks would treat this information fairly -- so I've decided to give
you these details about our relationship in the hopes of demonstrating my
sincerity to the American people." Then --- share away. Who knows what
interesting information might appear on Headline News in the next half
hour. ("CNN learned today, in an exclusive message from the President,
that he and .......") Well, you get the picture.

Just a final thought. If you did anything illegal with this, there is that
pesky field in the header labeled "Message-Id:"; and who knows how long ZD
may keep other information on that message. So I'd recommend caution.
-- RJ

*** Hoaxes -- RJ
RJ - This next section is somewhat long for the Digest, and could really
have been the beginnings of a GTmHH on Social Engineering. (And may still
become just that after more work.) But I wanted to get these two things
out in the open now.)

For as long as I have been on the net, there have been hoaxes of one sort
or another being sent around cyberspace. This is not likely to diminish or
cease anytime in the near future. But one thing that a hacker should be
aware of is the ever-present possibility of spoofs. This translates into
asking questions, and seeking source information from wherever it may be
obtained in order to verify the data presented. In just the last week, I
have received two of these "hoax" messages.

The first was quite harmless, except for the bandwidth it was taking up as
thousands of people crowded cyberspace with this cyber-litter.
It read as follows:

>I received this from Children's Hospital in Denver...after you read it
>you will want to follow the instructions and pass it on as well!
>>----Original Message-----
>>Subject: This is for Cancer Research... -Forwarded
>>>>This is why we all work in Cancer Research...and should be thankfule
>>for it!
>>No comedy here. It's about a seven year old girl with cancer.
>>Please read it and pass it on to as many people that you can.
>>Occasionally we get to use this medium for some actual good, rather
>>than trading barbs across the waves. And once in a while things like
>>this bring us back to reality, allowing us to count ourselves lucky in
>>Let's put our network to work here!
>> It will only take you a second to send this message.
>>>>Jessica Mydek is seven years old and is suffering from an acute and
>>very rare case of CEREBRAL CARCINOMA. This condition causes severe
>>Malignant brain tumors and is a terminal illness. The doctors have
>>given her six months to live. As part of her
>>dying wish, she wanted to start a chain letter to inform people of
>>this condition and to send people the message to live life to the
>>fullest and enjoy every moment, a chance that she will never have.
>>Furthermore, the American cancer society and several corporate
>>sponsors have agreed to donate three cents toward continuing cancer
>>research for every new person that gets forwarded this message.
>>Please give Jessica and all cancer victims a chance. Add acs@aol.com
>>to the list of people that you send this to so that the American
>>cancer society will be able to calculate how many people have gotten
>>this. If there are any questions, send them to
>>the American cancer society at acs@aol.com. Three cents for every
>>person that receives this letter turns out to be a lot of money
>>considering how many people will get this letter and how many people
>>they, in turn, pass it on to.Please go ahead and forward it to
>>whoever you know- it really doesn't take much to help out.
>>>>Jean Ann Linney, Ph.D.
>>Professor Department of Psychology
>>University of South Carolina
>>Columbia, SC 29208
>>>>PHONE: 803-777-4301

Just the type of message to tug at your hear strings and cause you to
forward this message to your entire contact list, pat yourself on the back
for a deed well done, and continue on with your work. Unfortunately
(unless, of course, if you're Jessica Mydek) this message is totally
fraudulent. Let's examine the message in detail, and note some things which
are "nice touches" and some others that should raise red flags.

Nice Touches:
** "I received this from Children's Hospital in Denver" -- Nice "appeal to
** "This is why we all work in Cancer Research" -- Inclusion, you're part
of "our" team
** "...seven year old girl with cancer" -- Ouch! Who can NOT want to help.
** "Let's put our network to work here!" -- Inclusion again.
** "As part of her dying wish" -- More heartstrings here
** "... it really doesn't take much to help out" -- Hey, you aren't THAT
lazy, are you??
** Finally, the Professors' Name, Degree and Phone # -- Another appeal to

The overall effect of these gambits is that you are left feeling as though
this HAS TO BE legitimate; after all, someone who was a Ph.D. and is a
Psychology professor at the University of South Carolina would certainly
not fall for a hoax .... would she? Well, as of right now, the answer to
this question is not known. Dr. Linney is in fact the Chair of the
Psychology department at the Univ. of SC. I have sent her an email message
requesting clarification of issues from her, but have yet to receive a

As I see it, there are at least two distinct possibilities here. First,
Dr. Linney's name was used without her knowledge or consent. This would
tend to indicate that a present or recent member of the academic body as
the university had determined to attempt to discredit her judgement for
some reason. Second, she may have fallen prey to the hoax, and
participated unknowingly.

What are the items in the message that should raise red flags?
** "and should be thankfule" -- Professionals rarely misspell words in a
public message
** "the American cancer society and several corporate sponsors have agreed
to donate three cents toward continuing cancer research for every new
person etc -- American Cancer Society is not capitalized. Furthermore,
they *collect* money for cancer research and then PERFORM CANCER RESEARCH -
they don't *donate* their money for cancer research.
** "Add acs@aol.com to the list ... forward it to whoever you know" -- That
the American Cancer Society would have a *single* AOL account for email is
stretching the imagination a bit. what is more likely to be happening here
is an address grabbing operation for sale of the addresses.

The solution here was as simple as two toll-free calls. (REALLY toll free,
no phreaking here.)
The first was to the ATtoll free directory for the 800 number to the
ACS, the second was to their National Cancer Information Center in Austin
TX. They quickly confirmed that the entire matter was a hoax. After
working out a few details with them, I sent the following reply to everyone
on my end of the chain (which was several hundred people!):

As a network security consultant, I frequently confirm information I
receive with the purported source. Unfortunately, I have confirmed with
the National Cancer Information Center in Austin TX that the below message
is fraudulent. I have also agreed to assist them in disseminating the
confirmation that it is false. It is indeed unfortunate that this type of
"chain letter" is started and wastes the time of so many caring individuals
who would like nothing better than to help a poor child. You can, however,
turn that which was meant for evil into something very good: a small,
donation to the American Cancer Society would accomplish the same effect.
Give them a call at 800-227-2345 for details.

RJ Gosselin, Sr.
Network Security Consultant

The second hoax message sounded much more ominous - but "Join The Crew" was
much easier to see through. It read like this:

>>If you receive an email titled "JOIN THE CREW" DO NOT open it.
>It will erase everything on your hard drive. Forward this letter out
>to as many people as you can. This is a new, very malicious virus and not
>many people know about it. This information was announced yesterday
>morning from IBM; please share it with everyone that might access the
>internet. Once again, pass this along to EVERYONE in your address book so
>that this may be stopped. Also, do not open or even look at any mail that
>says "RETURNED OR UNABLE TO DELIVERY" This virus will attach itself to
>your computer components and render them useless. Immediately delete any
>mail items that say this. AOL has said that this is a very dangerous virus
>and that there is NO remedy for it at this time. Please practice cautionary
>measures and forward this to all users.

When you start talking about erased hard drives -- people stand up and take
notice! Especially when IBM and AOL are the ones doing the warning. there
is only one small problem here, the virus and the danger are figments of
someone's imagination. But the clues, even without contacting IBM or AOL,
were easily detected.

First, email is text. Text cannot erase your hard disk ... period. The
only real danger here would be an attachment to an email which, if opened,
could possibly contain a virus of some sort, but *not* simply a text
message. No virus exists that can do this strictly from a text file being
opened. But, even if you didn't know that to be the case, one good source
of virus information is the Symantec Antivirus Research Center on their
website. (http://www.symantec.com/avcenter) They even have a section
dedicated to hoaxes, and our friend "Join the Crew" has their own listing.

But the same sort of social engineering gambits used in the first hoax are
used in the second, as well as the added element of fear. You can re-read
it and see their appeal to authority, the inclusion on a team or an elite
few, and the appeal for help.

Learn to be suspicious when you read anything that is unsolicited and asks
you to forward it to everybody you know. That is the biggest red flag of
all. -- RJ

*** Digest Q--
Would it not be possible to do a perfect email forge using IP-spoofing?
(probably to a PPP connection, as most PCs do not log the incoming
packets) If you were to spoof a server, then (as in the above note) you
could be traced by time of attack, but spoofing from a PC should have no
record. or am I mistaken? -Nethead

[Carolyn: The FIRST packet of a spoofed IP connection is always a true
packet. Someday soon I'm going to write a GTMHH on IP spoofing and how to
catch the spoofer anyhow. Folks, there is NO WAY to commit the perfect IP
From: Kenn ***** responding to Strider (our Mac Editor)
&gt>Strider wrote:
A true hacker enjoys exploring and working things out- programming is one
of the best ways to do this. Why not give away the fruits of your fun? Some
would say that being paid for it is selfish- although I doubt many people
of the cracker mentality would understand that: a typical cracker would, I
agree, like to take- breaking into a system, pirating "warez" and the like,
but not give. After all- where, they would say, is the gain in that?
- Strider
&gt>Ken Answered:
Civilization is the process of setting men free. Men do the work they
love and trade it by mutual agreement to mutual benefit so that both may
pursue their own productive avenues. Money is merely a tool to
facilitate that process. Being paid for anything IS selfish, and I think
that a rational selfishness is a virtue not a vice. I will not work for
free, because I value my life, and my time. I am proud of the products
of my efforts. But you've damned yourself, you're selfish too. If there
were no people, no community of intelligent, productive people willing
to make something to mutual benefit (like Linux), then you're all
selfish too. But is this bad? Is this evil? Think about it.
&gt>Strider Responded:
Perhaps you're right. But the people who need the money, as you say, create
shareware or commercial products. The people who create free products do so
on their own time, because they love to do it and don't NEED the money. If
more people showed generosity such as that, instead of charging 300% over
manufacturing and development for their products, more things in life would
be free, or at least cheaper. Releasing free software works against those
who charge too much for a shoddy product (WinNT is an example- full of
holes, many of the patches don't work, and although it's overall a decent
system, the only thing it can use to compete with freeBSD or linux is hype)
and displays an appreciation for community. It also completely destroys
elitism (or 331337ism, if you must) because all the source code is
accessible. Anyone can learn from anyone else's work, and that inspires
heightened learning and growth in any developmental community.
- Strider
&gt>Linux Answer from Tom Ben-Yehoshua

Regarding the anon dude installing red-hat:
Like him, I'm a newbie at linux (installed 1st time last week). I too
had some problems with LILO - I've installed latest Slackware on a P166,
64Mb, 3HD's (8+ Gb combined), 24x CDROM, all IDE - let's see if I can
help out :
1. first problem I've encountered was setting LILO as my boot
manager on a UMS DOS partition - everything looked fine until I tried to
boot without the boot diskette :
a. at first LILO would boot, writing LILO really slow and then
b. for some reason, after re-installing (exactly the same way) it
would write the entire LILO booting phrase (can't remember exactly what
it says in there and then giving me a prompt. If I just pressed enter,
it would try to mount a ramdrive, exit with an error and re-post the
dubious prompt..
2. well, time for a DOS fdisk... I've deleted the obscure UMS
partition, loaded linux boot disk and created an all linux partition...
Installed... no good... same as 1(a) - probably I'm missing something -
but who gives - fdisk;format c: /u/s/v:LINUX... and start over..
3. well I now have a DOS partition.. let's go.. Installed UMS DOS
this time without a linux boot partition :
DOS boots fine and now I have to directories on my HD :
Slackware (all linux install diskettes) and linux (guess...) - ha ha,
what's in the root dir? LODLIN16.ZIP.. guess what that is? Unzip, k, an
executable a batch file and a couple of readme's.. seems LODLIN stands
for LOAD LINUX (check the batch file for an example..) et' voila - linux
loaded ... Yee-pee
4. well next level was configuring X for a Number 9 Imagine128 and
a MAG Trinitron display...


Btw: I have an Award BIOS dated July 97 with virii detection disabled..

//Tom Ben-Yehoshua
*** Firewall Question

>>I have been reading GTmHH for some time now. I'm not a hacker nor am I a
>cracker but I do know my computers (maybe someday *grin*).

What I really like to hear is some in-depth explanation on how firewalls
work and how to trick them.


First you cannot trick a firewall, but you can defeat a firewall. How?
A firewall cannot protect against connections that don't go through it.
A firewall cannot provide 100% protection against all threats.

You want to know how a firewall works? Firewalls can be configured in three

1. Packet Filtering - worst way for configure a firewall. Packet filtering
works by dropping packets based on their source or destination addresses or
ports...decisions are made only from the contents of the current packet.

Administrators makes a list of acceptable machines and services, and a list
of unacceptable machines. It is easy to permit any IP access between host
A and B, or deny any access to B from any machine but A.

For example, one might want to allow any host to connect to machine A, but
only to send or receive mail. Other services may or may not be permitted.

Packet Filtering allows some control, but it is a dangerous and error-prone

2. Application-level gateway - represents the opposite extreme in firewall
design. Rather than using a general purpose mechanism to allow many
different kinds of traffic to flow, special purpose code can be used for
each desired application. Although this seems wasteful, it is likely to be
far more secure than any of the alternatives. One need not worry about
interactions among different sets of filter rules, nor about holes in
thousands of hosts offering nominally secure services to the outside.

Application gateways allow for logging of all incoming and outgoing traffic.

In other words an application firewall allows an SA to turn off all the
applications associated with the server, i.e.
IP redirects
IP route-cache
ip proxy-arp
All these services can be turned off using the application gateway setup.


3. The last and most secure configuration is Stateful Inspection.

Stateful Inspection technology accesses and analyzes data derived from all
communication layers. This "state" and "context" data is stored and updated
dynamically, providing virtual session information for tracking
connectionless protocols (e.g. RPC and UDP-based applications). Cumulative
data from the communication and application states, network configuration
and security rules, are used to generate an appropriate action, either
accepting, rejecting or encrypting the communication. Any traffic not
explicitly allowed by the security rules is dropped by default and real-time
security alerts are generated, providing the system manager with complete
network status.


>I'm using a computer which passes through the corporate firewall. I can
>use http but I can't use ftp. Can you please help me. Most of the cool
>wares that I want downloaded use ftp downloads not http.

DUH...if you worked for me I would have you fired in a minute. There is
most likely a reason that you cannot FTP out of your "corporation", they
were smart enough to turn off FTP.

Network Analyst

message "subscribe hh."
This is a list devoted to *legal* hacking! If you plan yo use any
information in this Digest or at our Web site to commit crime, go away! Foo
on you! Happy Hacker is a 501 (c) (3) tax exempt organization in the Unites
States operating under Shepherd's Fold Ministries. Yes! This is all a plot
to save your immortal souls!
For Windows questions, please write Roger Prata; for
Macs, write Strider; and Unix, Carolyn Meinel. Editor-in-chief is R.J. Gosselin. Webmaster is
Praying Mantis.

R.J. Gosselin, Sr.
Editor-In-Chief -- Happy Hacker Digest

"There is no way you're describing our system,
she could never have gotten past our security.

But I'm going to find her and see that she's prosecuted ...
she broke the law, and she's going to pay!"
President of "Blah Blah Bank"

--&gt&gt>Does anybody ELSE see a small discrepancy here ???????

For full story (and many others), download
"External Threats to Computer Security in Networked Systems"
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