Hackers Handbook - Millenium Edition/Hackers Handbook.iso/library/hack/gtmhh1-4.txt

Text File | 1997-09-25 | 20.7 KB | 560 lines

_______________________________________________________

GUIDE TO (mostly) HARMLESS HACKING

Vol. 1 Number 4

It's vigilante phun day! How get Usenet spammers kicked off their ISPs.
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How do you like it when your sober news groups get hit with 900 number sex
ads and Make Money Fast pyramid schemes? If no one ever made those guys pay
for their effrontery, soon Usenet would be inundated with crud.

It's really tempting, isn't it, to use our hacking knowledge to blow these
guys to kingdom come. But many times that's like using an atomic bomb to
kill an ant. Why risk going to jail when there are legal ways to keep these
vermin of the Internet on the run?

This issue of Happy hacker will show you some ways to fight Usenet spam.

Spammers rely on forged email and Usenet posts. As we learned in the second
Guide to (mostly) Harmless Hacking, it is easy to fake email. Well, it's
also easy to fake Usenet posts.

*****************
Newbie Note #1: Usenet is a part of the Internet consisting of the system of
on-line discussion groups called "news groups." Examples of news groups are
rec.humor, comp.misc, news.announce.newusers, sci.space.policy, and alt.sex.
There are well over 10,000 news groups. Usenet started out in 1980 as a Unix
network linking people who wanted -- you guessed it -- to talk about Unix.
Then some of the people wanted to talk about stuff like physics, space
flight, barroom humor, and sex. The rest is history.
*****************

Here's a quick summary of how to forge Usenet posts. Once again, we use the
technique of telnetting to a specific port. The Usenet port usually is open
only to those with accounts on that system. So you will need to telnet from
your ISP shell account back into your own ISP as follows:

    telnet news.myISP.com nntp

where you substitute the part of your email address that follows the @ for
"myISP.com." You also have the choice of using "119" instead of "nntp."

With my ISP I get this result:

    Trying 198.59.115.25 ...
    Connected to sloth.swcp.com.
    Escape character is '^]'.
    200 sloth.swcp.com InterNetNews NNRP server INN 1.4unoff4 05-            Mar-96
ready (posting)

Now when we are suddenly in a program that we don't know too well, we ask for:

    help

And we get:

    100 Legal commands
          authinfo user Name|pass Password|generic <prog> <args>
          article [MessageID|Number]
          body [MessageID|Number]
          date
          group newsgroup
         head [MessageID|Number]
         help
         ihave
         last
        list [active|newsgroups|distributions|schema]
        listgroup newsgroup
        mode reader
        newgroups yymmdd hhmmss ["GMT"] [<distributions>]
         newnews newsgroups yymmdd hhmmss ["GMT"]                         [<distributions>]
          next
          post
          slave
          stat [MessageID|Number]
          xgtitle [group_pattern]
          xhdr header [range|MessageID]
          xover [range]
          xpat header range|MessageID pat [morepat...]
          xpath MessageID
    Report problems to <[e-mail]>

Use your imagination with these commands. Also, if you want to forge posts
from an ISP other than your own, keep in mind that some Internet host
computers have an nntp port that requires either no password or an easily
guessed password such as "post." But-- it can be quite an effort to find an
undefended nntp port. So, because you usually have to do this on your own
ISP, this is much harder than email forging.

Just remember when forging Usenet posts that both faked email and Usenet
posts can be easily detected -- if you know what to look for. And it is
possible to tell where they were forged. Once you identify where spam really
comes from, you can use the message ID to show the sysadmin who to kick out.

Normally you won't be able to learn the identity of the culprit yourself.
But you can get their ISPs to cancel their accounts!

Sure, these Spam King types often resurface with yet another gullible ISP.
But they are always on the run. And, hey, when was the last time you got a
Crazy Kevin "Amazing Free Offer?" If it weren't for us Net vigilantes, your
email boxes and news groups would be constantly spambombed to kingdom come.

And -- the spam attack I am about to teach you is perfectly legal! Do it and
you are a certifiable Good Guy. Do it at a party and teach your friends to
do it, too. We can't get too many spam vigilantes out there!

The first thing we have to do is review how to read headers of Usenet posts
and email.

The header is something that shows the route that email or Usenet post took
to get into your computer. It gives the names of Internet host computers
that have been used in the creation and transmission of a message. When
something has been forged, however, the computer names may be fake.
Alternatively, the skilled forger may use the names of real hosts. But the
skilled hacker can tell whether a host listed in the header was really used.

First we'll try an example of forged Usenet spam. A really good place to
spot spam is in alt.personals. It is not nearly as well policed by anti-spam
vigilantes as, say, rec.aviation.military. (People spam fighter pilots at
their own risk!)

So here is a ripe example of scam spam, as shown with the Unix-based Usenet
reader, "tin."

Thu, 22 Aug 1996 23:01:56        alt.personals       Thread  134 of  450
Lines 110   >>>>FREE INSTANT COMPATIBILITY CHECK FOR SEL   No responses
[e-mail]      glennys e clarke at OzEmail Pty Ltd - Australia

CLICK HERE FOR YOUR FREE INSTANT COMPATIBILITY CHECK!
http://www.perfect-partners.com.au

WHY SELECTIVE SINGLES CHOOSE US

At Perfect Partners (Newcastle) International we are private and
confidential.  We introduce ladies and gentlemen for friendship
and marriage.  With over 15 years experience, Perfect Partners is one
of the Internet's largest, most successful relationship consultants.


Of course the first thing that jumps out is their return email address. Us
net vigilantes used to always send a copy back to the spammer's email address.

On a well-read group like alt.personals, if only one in a hundred readers
throws the spam back into the poster's face, that's an avalanche of mail
bombing. This avalanche immediately alerts the sysadmins of the ISP to the
presence of a spammer, and good-bye spam account.

So in order to delay the inevitable vigilante response, today most spammers
use fake email addresses.

But just to be sure the email address is phony, I exit tin and at the Unix
prompt give the command:

    whois ozemail.com.au

We get the answer:

    No match for "OZEMAIL.COM.AU"

That doesn't prove anything, however, because the "au" at the end of the
email address means it is an Australian address. Unfortunately "whois" does
not work in much of the Internet outside the US.

The next step is to email something annoying to this address. A copy of the
offending spam is usually annoying enough. But of course it bounces back
with a no such address message.

Next I go to the advertised Web page. Lo and behold, it has an email address
for this outfit, [e-mail]. Why am I not surprised
that it is different from the address in the alt.personals spam?

We could stop right here and spend an hour or two emailing stuff with 5 MB
attachments to [e-mail]. Hmmm, maybe gifs of
mating hippopotami?

***************************
You can go to jail note! Mailbombing is a way to get into big trouble.
According to computer security expert Ira Winkler, "It is illegal to mail
bomb a spam.  If it can be shown that you maliciously caused a financial
loss, which would include causing hours of work to recover from a spamming,
you are criminally liable.  If a system is not configured properly, and has
the mail directory on the system drive, you can take out the whole system.
That makes it even more criminal."
***************************

Sigh. Since intentional mailbombing is illegal, I can't send that gif of
mating hippopotami. So what I did was email one copy of that spam back to
perfect.partners. Now this might seem like a wimpy retaliation. And we will
shortly learn how to do much more. But even just sending one email message
to these guys may become part of a tidal wave of protest that knocks them
off the Internet. If only one in a thousand people who see their spam go to
their Web site and email a protest, they still may get thousands of protests
from every post. This high volume of email may be enough to alert their
ISP's sysadmin to spamming, and good-bye spam account.

Look at what ISP owner/operator Dale Amon has to say about the power of
email protest:

"One doesn't have to call for a 'mail bomb.' It just happens. Whenever I see
spam, I automatically send one copy of their message back to them. I figure
that thousands of others are doing the same. If they (the spammers) hide
their return address, I find it and post it if I have time. I have no
compunctions and no guilt over it."

Now Dale is also the owner and technical director of the largest and oldest
ISP in Northern Ireland, so he knows some good ways to ferret out what ISP
is harboring a spammer. And we are about learn one of them.

Our objective is to find out who connects this outfit to the Internet, and
take out that connection! Believe me, when the people who run an ISP find
out one of their customers is a spammer, they usually waste no time kicking
him or her out.

Our first step will be to dissect the header of this post to see how it was
forged and where.

Since my newsreader (tin) doesn't have a way to show headers, I use the "m"
command to email a copy of this post to my shell account.

It arrives a few minutes later. I open it in the email program "Pine" and
get a richly detailed header:

Path:
sloth.swcp.com!news.ironhorse.com!news.uoregon.edu!vixen.cso.uiuc.edu!news.s
tealth.net!nntp04.primenet.com!nntp.primenet.com!gatech!nntp0.mindspring.com
!news.mindspring.com!uunet!in2.uu.net!OzEmail!OzEmail-In!news
From: glennys e clarke <[e-mail]>
NNTP-Posting-Host: 203.15.166.46
Mime-Version: 1.0
Content-Type: text/plain
Content-Transfer-Encoding: 7bit
X-Mailer: Mozilla 1.22 (Windows; I; 16bit)

The first item in this header is definitely genuine: sloth.swcp.com. It's
the computer my ISP uses to host the news groups. It was the last link in
the chain of computers that have passed this spam around the world.

*******************
Newbie Note #2: Internet host computers all have names which double as their
Net addresses. "Sloth" is the name of one of the computers owned by the
company which has the "domain name" swcp.com. So "sloth" is kind of like the
news server computer's first name, and "swcp.com" the second name. "Sloth"
is also kind of like the street address, and "swcp.com" kind of like the
city, state and zip code. "Swcp.com" is the domain name owned by Southwest
Cyberport. All host computers also have numerical versions of their names,
e.g. 203.15.166.46.
*******************

Let's next do the obvious. The header says this post was composed on the
host 203.15.166.46. So we telnet to its nntp server (port 119):

    telnet 203.15.166.46 119

We get back:

Trying 203.15.166.46 ...
telnet: connect: Connection refused

This looks a lot like a phony item in the header. If this really was a
computer that handles news groups, it should have a nntp port that accepts
visitors. It might only accept a visitor for the split second it takes to
see that I am not authorized to use it. But in this case it refuses any
connection whatever.

There is another explanation: there is a firewall on this computer that
filters out packets from anyone but authorized users. But this is not common
in an ISP that would be serving a spammer dating service. This kind of
firewall is more commonly used to connect an internal company computer
network with the Internet.

Next I try to email postmaster@203.15.166.46 with a copy of the spam. But I
get back:

Date: Wed, 28 Aug 1996 21:58:13 -0600
From: Mail Delivery Subsystem <[e-mail]>
To: [e-mail]
Subject: Returned mail: Host unknown (Name server: 203.15.166.46: host not
found)

The original message was received at Wed, 28 Aug 1996 21:58:06 -0600
from cmeinel@localhost

   ----- The following addresses had delivery problems -----
postmaster@203.15.166.46  (unrecoverable error)

   ----- Transcript of session follows -----
501 postmaster@203.15.166.46...  550 Host unknown (Name server: 203.15.166.46:
host not found)

   ----- Original message follows -----
Return-Path: cmeinel
Received: (from cmeinel@localhost) by kitsune.swcp.com (8.6.9/8.6.9) id

OK, it looks like the nntp server info was forged, too.

Next we check the second from the top item on the header. Because it starts
with the word "news," I figure it must be a computer that hosts news groups,
too. So I check out its nntp port:

telnet news.ironhorse.com nntp

And the result is:

Trying 204.145.167.4 ...
Connected to boxcar.ironhorse.com.
Escape character is '^]'.
502 You have no permission to talk.  Goodbye.
Connection closed by foreign host

OK, we now know that this part of the header references a real news server.
Oh, yes, we have also just learned the name/address of the computer
ironhorse.com uses to handle the news groups: "boxcar."

I try the next item in the path:

telnet news.uoregon.edu nntp

And get:

Trying 128.223.220.25 ...
Connected to pith.uoregon.edu.
Escape character is '^]'.
502 You have no permission to talk.  Goodbye.
Connection closed by foreign host.

OK, this one is a valid news server, too. Now let's jump to the last item in
the header: in2.uu.net:

    telnet in2.uu.net nntp

We get the answer:

    in2.uu.net: unknown host

There is something fishy here. This host computer in the header isn't
currently connected to the Internet. It probably is forged. Let's check the
domain name next:

whois uu.net

The result is:

UUNET Technologies, Inc. (UU-DOM)
   3060 Williams Drive Ste 601
   Fairfax, VA 22031
   USA

   Domain Name: UU.NET

   Administrative Contact, Technical Contact, Zone Contact:
      UUNET, AlterNet [Technical Support]  (OA12)  [e-mail]
      [phone]
   Billing Contact:
      Payable, Accounts  (PA10-ORG)  [e-mail]
      [phone]
Fax: [phone]

   Record last updated on 23-Jul-96.
   Record created on 20-May-87.

   Domain servers in listed order:

   NS.UU.NET                    137.39.1.3
   UUCP-GW-1.PA.DEC.COM         16.1.0.18 204.123.2.18
   UUCP-GW-2.PA.DEC.COM         16.1.0.19
   NS.EU.NET                    192.16.202.11


The InterNIC Registration Services Host contains ONLY Internet Information
(Networks, ASN's, Domains, and POC's).
Please use the whois server at nic.ddn.mil for MILNET Information.

So uu.net is a real domain. But since the host computer in2.uu.net listed in
the header isn't currently connected to the Internet, this part of the
header may be forged. (However, there may be other explanations for this, too.)

Working back up the header, then, we next try:

telnet news.mindspring.com nntp

I get:

Trying 204.180.128.185 ...
Connected to news.mindspring.com.
Escape character is '^]'.
502 You are not in my access file.  Goodbye.
Connection closed by foreign host.

Interesting. I don't get a specific host name for the nntp port. What does
this mean? Well, there's a way to try. Let's telnet to the port that gives
the login sequence. That's port 23, but telnet automatically goes to 23
unless we tell it otherwise:

telnet news.mindspring.com

Now this is phun!

Trying 204.180.128.166 ...
telnet: connect to address 204.180.128.166: Connection refused
Trying 204.180.128.167 ...
telnet: connect to address 204.180.128.167: Connection refused
Trying 204.180.128.168 ...
telnet: connect to address 204.180.128.168: Connection refused
Trying 204.180.128.182 ...
telnet: connect to address 204.180.128.182: Connection refused
Trying 204.180.128.185 ...
telnet: connect: Connection refused

Notice how many host computers are tried out by telnet on this command! They
must all specialize in being news servers, since none of them handles logins.

This looks like a good candidate for the origin of the spam. There are 5
news server hosts. Let's do a whois command on the domain name next:

    whois mindspring.com

We get:

MindSpring Enterprises, Inc. (MINDSPRING-DOM)
   1430 West Peachtree Street NE
   Suite 400
   Atlanta, GA 30309
   USA

   Domain Name: MINDSPRING.COM

   Administrative Contact:
      Nixon, J. Fred  (JFN)  [e-mail]
      404-815-0770
   Technical Contact, Zone Contact:
      Ahola, Esa  (EA55)  [e-mail]
      [phone]
   Billing Contact:
      Peavler, K. Anne  (KAP4)  [e-mail]
      404-815-0770 (FAX) 404-815-8805

   Record last updated on 27-Mar-96.
   Record created on 21-Apr-94.

   Domain servers in listed order:

   CARNAC.MINDSPRING.COM        204.180.128.95
   HENRI.MINDSPRING.COM         204.180.128.3

*********************
Newbie Note #3: The whois command can tell you who owns a domain name. The
domain name is the last two parts separated by a period that comes after the
"@" in an email address, or the last two parts separated by a period in a
computer's name.
*********************

I'd say that Mindspring is the ISP from which this post was most likely
forged. The reason is that this part of the header looks genuine, and offers
lots of computers on which to forge a post. A letter to the technical
contact at [e-mail] with a copy of this post may get a result.

But personally, I would simply go to their Web site and email them a protest
from there. Hmmm, maybe a 5 MB gif of mating hippos? Even if it is illegal?

But systems administrator Terry McIntyre cautions me:

"One needn't toss megabyte files back ( unless, of course, one is helpfully
mailing a copy of the offending piece back, just so that the poster knows
what the trouble was. )

"The Law of Large Numbers of Offendees works to your advantage. Spammer
sends one post to 'reach out and touch' thousands of potential customers.

"Thousands of Spammees send back oh-so-polite notes about the improper
behavior of the Spammer. Most Spammers get the point fairly quickly.

"One note - one _wrong_ thing to do is to post to the newsgroup or list
about the inappropriateness of any previous post. Always, always, use
private email to make such complaints. Otherwise, the newbie inadvertently
amplifies the noise level for the readers of the newsgroup or email list."

Well, the bottom line is that if I really want to pull the plug on this
spammer, I would send a polite note including the Usenet post with headers
intact to the technical contact and/or postmaster at each of the valid links
I found in this spam header. Chances are that they will thank you for your
sleuthing.

Here's an example of an email I got from Netcom about a spammer I helped
them to track down.

From: Netcom Abuse Department <[e-mail]>
Reply-To: <[e-mail]>
Subject: Thank you for your report

Thank you for your report.  We have informed this user of our policies, and
have taken appropriate action, up to, and including cancellation of the
account, depending on the particular incident. If they continue to break
Netcom policies we will take further action.

The following issues have been dealt with:
    [e-mail]
    [e-mail]
    [e-mail]
    [e-mail]
    [e-mail]
    [e-mail]
    [e-mail]
    [e-mail]
    [e-mail]
    [e-mail]
    [e-mail]
    [e-mail]
    [e-mail]
    [e-mail]
    [e-mail]
    [e-mail]
    [e-mail]
    [e-mail]
    [e-mail]
    [e-mail]
    [e-mail]
    [e-mail]
    [e-mail]
    [e-mail]
    [e-mail]
    [e-mail]
    [e-mail]
    [e-mail]
    [e-mail]
    [e-mail]
    [e-mail]
    [e-mail]
    [e-mail]
    [e-mail]
    [e-mail]
    [e-mail]
    [e-mail]
    [e-mail]

Sorry for the length of the list.

Spencer
Abuse Investigator
___________________________________________________________________
NETCOM Online Communication Services                   Abuse Issues
24-hour Support Line: 408-983-5970                     [e-mail]
**************

OK, I'm signing off for this column. I look forward to your contributions to
this list. Happy hacking -- and don't get busted!

__________________________________________________________________

Want to share some kewl stuph? Tell me I'm terrific? Flame me? For the first
two, I'm at [e-mail]. Please direct flames to
dev/[e-mail]. Happy hacking!
_______________________________________________________
Copyright 1996 Carolyn P. Meinel. You may forward the GUIDE TO (mostly)
HARMLESS HACKING as long as you leave this notice at the end. To subscribe,
email [e-mail] with message "subscribe hacker
<[e-mail]>" substituting your real email address for Joe Blow's.
___________________________________________________________________