The Risks Digest

The RISKS Digest

Forum on Risks to the Public in Computers and Related Systems

ACM Committee on Computers and Public Policy, Peter G. Neumann, moderator

Volume 19 Issue 90

Friday 7 August 1998


o Software flaw exposes e-mail programs ...
Edupage Editors
o Long-filename security bug in e-mail readers and safe languages
Paul Haahr
o ISSalert: ISS Security Advisory: cDc BackOrifice Backdoor
o Re: Yorktown/NT/Security threads
Mitch Stanek
o 50M Lines of Windows NT?
Fred Ballard
o Wiretap and surveillance update
Declan McCullagh
o Power surge hits telephones and data comms
John Colville
o Interesting GPS interference
Martin Poole
o Re: USS Yorktown: WinNT not the fault
A. Penguin
o Re: Yorktown dead in water after divide by 0
Jonathan Mayer
o More on SOHO
Nancy Leveson
o New Jersey Y2K car inspection stickers
Dan Wallach
o Bug-free millennium for Railtrack
Mike Ellims
o White House Calm, DoD Nervous About Y2K
Declan McCullagh
o Re: html "referer" field
Doneel Edelson
o Re: "Cracking DES"
Martin Minow
o SEI 1998 Software Engineering Symposium
Carol Biesecker
o Info on RISKS (comp.risks)

Software flaw exposes e-mail programs ...

Edupage Editors <>
Thu, 30 Jul 1998 17:06:13 -0400
A security flaw found in several of the most widely used e-mail programs
(Microsoft Outlook Express, Microsoft Outlook 98, and Netscape Mail) could
be used by malicious persons to send computers using those programs a virus
that could destroy or steal data and could cause those computers to crash.
The flaw, which is known as a buffer overflow error, occurs when a program
fails to check the length of each character string.  This failure means that
a string too large to fit into an allotted memory location will lock up the
program and fool the operating system into running attacker code in its
place.  Whereas new languages such as Java have built-in safeguards to
prevent this kind of programmer error, older languages such as C and C++ do
not.  Computer security specialist Steven Bellovin says, "C makes it too
easy to slice your fingers off, and programmers all over the world are doing
so with great regularity."  (*The New York Times*, 30 Jul 1998; Edupage, 30
July 1998.  This is the Finnish find.)

Long-filename security bug in e-mail readers and safe languages

Paul Haahr <>
Wed, 29 Jul 1998 08:20:52 -0700 (PDT)
There's been a lot of coverage of the potential security hole in Microsoft
and Netscape's mail readers.  Most reports note that this is the same kind
of bug exploited by Robert Morris's Internet worm: overflow a fixed-length
buffer on the stack to predictably sabotage the control flow of the program.

What all the reports I've read appear to be missing is that bugs like this
are almost inevitable in C or C++, yet pose almost no security issues in
safer programming languages, including as Java, Lisp, Ada, Smalltalk,
Modula-3, Eiffel, ML, etc.

That is, the consequence of overflowing an array in Java is that an
ArrayIndexOutOfBoundsException is thrown.  No stack gets overwritten, no
data gets corrupted.  The program fails, but it does so in a sensible,
predictable manner.  Contrast this with C or C++, where the existence of a
single, unchecked array access based on user-provided input is sufficient to
expose gaping security holes.

Just as the use of four digits for dates was considered wasteful or
unnecessary in the past, the use of safe languages is often thought a luxury
today.  It isn't.

ISSalert: ISS Security Advisory: cDc BackOrifice Backdoor

X-Force <>
Thu, 6 Aug 1998 11:04:49 -0400 (EDT)
ISS Security Alert Advisory
August 6th, 1998

Cult of the Dead Cow Back Orifice Backdoor


A hacker group known as the Cult of the Dead Cow has released a Windows
95/98 backdoor named 'Back Orifice' (BO).  Once installed this backdoor
allows unauthorized users to execute privileged operations on the affected

Back Orifice leaves evidence of its existence and can be detected and
removed.  The communications protocol and encryption used by this backdoor
has been broken by ISS X-Force.

A backdoor is a program that is designed to hide itself inside a target
host in order to allow the installing user access to the system at a later
time without using normal authorization or vulnerability exploitation.

The BO program is a backdoor designed for Windows 95/98. Once installed it
allows anyone who knows the listening port number and BO password to
remotely control the host.  Intruders access the BO server using either a
text or graphics based client.  The server allows intruders to execute
commands, list files, start silent services, share directories, upload and
download files, manipulate the registry, kill processes, list processes, as
well as other options.

Encrypted Communications:
All communications between backdoor client and the server use the User
Datagram Protocol (UDP).  All data sent between the client and server is
encrypted, however it is trivial to decrypt the data sent. X-Force has been
able to decrypt BO client requests without knowing the password and use the
gathered data to generate a password that will work on the BO server.

The way that BO encrypts its packets is to generate a 2 byte hash from the
password, and use the hash as the encryption key. The first 8 bytes of all
client request packets use the same string: "*!*QWTY?", thus it is very
easy to brute force the entire 64k key space of the password hash and
compare the result to the expected string. Once you know the correct hash
value that will decrypt packets, it is possible to start generating and
hashing random passwords to find a password that will work on the BO
server. In our tests in the X-Force lab, this entire process takes only a
few seconds, at most, on a Pentium-133 machine. With our tools we have been
able to capture a BO request packet, find a password that will work on the
BO server, and get the BO server to send a dialog message to warn the
administrator and kill its own process.

Determining if BO has been installed on your machine:
The BO server will do several things as it installs itself on a target

* Install a copy of the BO server in the system directory
(c:\windows\system) either as " .exe" or a user specified file name.

* Create a registry key under
with the file name of the server file name and a description field of
either "(Default)" or a user specified description.

* The server will begin listening on UDP port 31337, or a UDP port
specified by the installer.  You can configure RealSecure to monitor for
network traffic on the default UDP 31337 port for possible warning signs.
In order to determine if you are vulnerable:

1. Start the regedit program (c:\windows\regedit.exe).
2. Access the key
Look for any services that may not have been intentionally installed on the
machine.  If the length of one of these file is close to 124,928 (give or
take 30 bytes) then it is probably BO.

Recommended action:
BO can be removed by deleting the server and removing its registry entry.
 If possible, you should back up all user data, format your hard drive, and
reinstall all operating systems and software on the infected machine.
However, if someone has installed BO on your machine, then it is most likely
part of a larger security breach.  You should react according to your site
security policy.

Determining the password and configuration of an installed BO:
1. Using a text editor like notepad, view the server exe file.
2. If the last line of the file is '8 8$8(8,8084888<8@8D8H8L8P8T8X8\8'8d8h8l8',
then the server is using the default configuration.  Otherwise, the
configuration will be the last several lines of this file, in this order:

<service description>
<port number>
<optional plugin information>

Back Orifice provides an easy method for intruders to install a backdoor on
a compromised machine.  Back Orifice's authentication and encryption is
weak, therefore an administrator can determine what activities and
information is being sent via BO.  Back Orifice can be detected and
removed.  This backdoor only works on Windows 95 and Windows 98 for now
and not currently on Windows NT.

  [Copyright (c) 1998 by Internet Security Systems, Inc.
  Permission is hereby granted for the redistribution of this alert
  electronically.  It is not to be edited in any way without express consent
  of X-Force.  If you wish to reprint the whole or any part of this alert in
  any other medium excluding electronic medium, please e-mail
  for permission.]

The information within this paper may change without notice. Use of this
information constitutes acceptance for use in an AS IS condition. There are
NO warranties with regard to this information. In no event shall the author
be liable for any damages whatsoever arising out of or in connection with
the use or spread of this information. Any use of this information is at
the user's own risk.

X-Force Vulnerability and Threat Database:
Please send suggestions, updates, and comments to:
X-Force <> of Internet Security Systems, Inc.

Re: Yorktown/NT/Security threads

mitch <>
Wed, 29 Jul 1998 08:21:09 -0700
"More kindling for the fire:,4,24643,00.html

Yet another serious NT security bug announced and acknowledged by Microsoft.
A flaw in the OS would allow any ordinary network user to impersonate an NT
system administrator.  There is also the *possibility* that anyone with
Internet access could do the same thing.

How secure is national security?  Let's hope that NT has not found its way
aboard any SSBNs...  Linux anyone?

Mitch Stanek

50M Lines of Windows NT?

Fred Ballard <>
Fri, 31 Jul 1998 17:56:21 -0500
I heard part of National Public Radio's Science Friday on July 24
called "Beyond Windows" (you can see more -- a list of the guests,
for instance -- and hear the show at

The part I heard was at the end of the show.  Someone said that it's rumored
Windows NT 5.0 will contain 50M lines of C code.  Several comments followed:
C was too primitive for the task, but C++ was too complex; 30M lines of the
50M are probably IF statements figuring out what environment it's running in
and acting accordingly; isn't 50M lines of code something like what the Star
Wars missile defense system was going to take and nobody thought that would
ever work.

Fred Ballard

Wiretap and surveillance update

Declan McCullagh <>
Fri, 31 Jul 1998 11:16:41 -0700 (PDT)
The U.S. Department of Justice is now saying that it does not support the
proposed amendments to the Communications Assistance for Law Enforcement Act
(CALEA) that the FBI had provided to Senators a few weeks ago (See EPIC
Alert 5.10).  Assistant Attorney General Steven Colgate characterizes the
amendment as a "staff document" and describes the language on emergency
access to cell phone location information without a warrant as "boneheaded."
However, Senate staff reports receiving calls from a senior FBI lobbyist
pushing for the amendment even after the New York Times reported on the
Bureau proposal.

>From POLITECH -- the moderated mailing list of politics and technology
To subscribe: send a message to with this text:
  subscribe politech
More information is at

Power surge hits telephones and data comms

John Colville <>
Wed, 5 Aug 1998 11:18:18 +1000 (EST)
>From *Sydney Morning Herald*, 5 Aug 1998, p2:

Electronic chaos as exchange overloads
by Andrew Cassell [with JC additions from ABC radio]

Bank computers crashed and data and fax lines were cut across the State
yesterday when a power surge hit Telstra's Haymarket exchange in the city.
The breakdown created extra queues at banks as computers, automatic teller
machines and EFTPOS outlets failed.  TAB [off course betting] agencies
around the State were also affected and 3,500 Telstra customers in Mascot
and 400 in Randwick lost phone services.

The shutdown, between 12.20 pm and 1.20 pm, could have been much worse,
Telstra's public affairs manager, Ms Kerrina Lawrence, said, but fast action
by technicians had stopped the problem spreading through the whole of
Sydney.  [The technicians noticed the surge and moved isolate things
manually.  They then had to do 1000 manual resets.  Mascot and Randwick are
a few km from the affected exchange. Presumably, they didn't move to manual
before the surge hit those exchanges as well.]

Telstra call connect and 013 [Directory Assistance] services had also been
disrupted, and in some cases, disconnected because of the surge, with the
situation made worse by customers clogging up lines trying to get through.
Problems with those services were continuing last night.  [3 of the 5
largest Australian banks reported problems. Commonwealth Bank was affected
until 5 pm.]

John Colville: Centre for Teaching and Learning, Computing Sciences,
+61-2-9514-2487 (1998)

Interesting GPS interference

Martin Poole <>
Thu, 6 Aug 1998 12:05:12 +0100
The following URL documents an interesting case of GPS interference.

Martin Poole, Perot Systems Europe

  [The item is "Detrimental Effects of Installing Consumer Electronics on
  Ships" by Ken Hamer of Offshore Systems Ltd., Vancouver, presented
  at RTCM, May 1997.  OSL makes ECDIS (Electronic Chart Display and
  Information System), based on a combination of GPS receiver and
  differential beacon receiver that enhances GPS accuracy -- in combination
  referred to as Differential GPS (DGPS).  The article documents their
  efforts to identify the cause of a persistent erratic failure mode that
  occurred aboard the M.V. Manatoulin, a Great Lakes cargo ship.  The
  narrative reads a little like a mystery story, and eventually leads to
  the captain's quarters' television antenna -- which used a cheap and noisy
  RF amplifier.  PGN Stark Abstracting]

Re: USS Yorktown: WinNT not the fault.

"A. Penguin" <>
Wed, 29 Jul 1998 20:29:33 -0400
We seem to be too quick to blame WinNT for putting USS Yorktown dead in the
water.  The problem was described as someone entering a zero, after which a
database overflowed and the propulsion system failed.  That sounds like a
bug in an application program, not the esteemed operating system!  We're
unlikely to learn more about the application itself.  Visual A(da), Visual
B(asic), Visual C.  One could easily forget which language one is supposed
to program with.

This leads to the following thought - if a technophobe were intending to
join the modern armed forces, which is the safest branch?  It would
certainly be less comfortable to have the ship handicapped by a systems
failure in the submarine and air force services, and best in the Army where
one could always bring up the backup systems: your feet.

Andy Fraser

Re: Yorktown dead in water after divide by 0

Jonathan Mayer <>
Mon, 27 Jul 1998 23:06:26 -0700 (PDT)
A simple solution: kill two birds with one stone by forcing Microsoft to GPL
the source code to Windows NT.

1. we will finally be able to patch NT to make it secure
   and reliable enough for mission critical applications.

2. the software industry will be freed of an unfriendly tyrant,
   and Microsoft will be forced to compete in the office software
   arena on a freshly levelled playing field.

"I am commandeering this source in the name of national security!"  :-)

Jonathan <>

More on SOHO (RISKS-19.87)

Wed, 29 Jul 1998 13:39:37 +0500
*Aviation Week and Space Technology*, 20 Jul 1998

Investigators believe two software errors and an improper command led to a
loss of contact with the NASA/European Space Agency Solar and Heliospheric
Observatory (SOHO) spacecraft on 24 Jun 1998.  Recovery efforts are
underway.  An error in a preprogrammed command sequence resulted in an
incorrect gyroscope reading, sending the spacecraft into an Emergency Sun
Reacquisition (ESR) mode.  A separate command sequence lacked code to
activate a gyro needed for control when the spacecraft entered the ESR mode.
Finally, a decision to command SOHO to turn off a gyro in response to
unexpected telemetry caused the spacecraft to enter a series of ESRs, and
ultimately led to loss of control, the agencies said.

Nancy Leveson

New Jersey Y2K car inspection stickers

Dan Wallach <dwallach@CS.Princeton.EDU>
Wed, 29 Jul 1998 11:46:25 -0400
On the lighter side of the Y2K problem, I recently received the following
letter from the New Jersey Division of Motor Vehicles:

  Dear Motorist:

  Due to law enforcement concerns over the similarity of the green, year
  2000 inspection stickers with the recently expired green stickers
  issued in 1997, the Division has discontinued use of the green sticker
  and is replacing it with a new orange, year 2000 sticker.

  Our records indicate that a year 2000 sticker was issued for your
  vehicle earlier this year ... We will replace your present sticker
  with a new orange one.

At least we have the New Jersey government sticking it to us on year 2000
compliance.  Still, even with a new orange Y2K sticker, I wonder if my car
will be truly Y2K compliant.

Dan Wallach                  Princeton University, CS Department

  [Crockwork Orange?  PGN]

Bug-free millennium for Railtrack

Mike Ellims <>
Fri, 31 Jul 1998 12:27:20 +0100
According to *The Guardian* (30 Jul 1998), Railtrack which was formed out of
the old British Rail has no safety critical computer systems that need to be
debugged.  This is a legacy of underfunding over the past 20 years before it
was privatized.  The article quotes Railtrack as having 750 manual level
signal boxes, 250 power boxes introduced in the 1980's and 9 electronically
controlled boxes.  It has therefore decided to downgrade it's preparation
for the year 2000 as it rushes forward; out of the steam age.

Mike Ellims, Pi Technology, +44(0)1223441256

White House Calm, DoD Nervous About Y2K

Declan McCullagh <>
Wed, 29 Jul 1998 12:29:15 -0700 (PDT),2326,201980729-14220,00.html / The Netly News, 29 Jul 1998

White House Calm, DoD Nervous About Y2K
By Declan McCullagh (

Few were surprised when John Koskinen, the White House's Y2K czar, said
yesterday that "it's too early to say that in fact there are going to be
major disruptions" due to the Year 2000 problem.  Koskinen's
work-hard-and-don't-be-scared advice is what the Clinton administration has
been saying all along.

But some of the Y2K experts Koskinen brought with him to a National Press
Club briefing yesterday offered some dismaying details. Usually if, say, a
4,000-megawatt power plant gives up the ghost, it's no big deal. The
electric industry is pretty good at planning for these sorts of
breakdowns. But if dozens crash within a few hours on 1-1-00? "It's a very
complex system," admitted Michael Gent, president of the North American
Electric Reliability Council. "It's probably the most complex system every
invented by man, more complicated than a moon shot." Gent nevertheless
predicted that even if today were December 31, 1999, "the lights would stay
on in most places."

If they go out, it'll be the fault of the private sector, not the feds,
Koskinen said.  Contradicting the now-popular belief that the federal
government's computers are in the worst shape, he predicted that "the
threats to the economy and the public are not going to be federal systems."

Already prepared to accept his part is John Hamre, deputy secretary of
defense. "I think we're probably going to be the poster child for failure,"
he said last week during a speech to Fortune 500 executives.  "Nobody cares
if the Park Services computers don't come on. OK? But what's going to happen
if some do[n't] in the DoD?"

Re: html "referer" field

"Edelson, Doneel" <>
Wed, 5 Aug 1998 11:05:04 -0500
There is a good article on the html "referer" field in the magazine Web
Techniques, Sept. 1998, page 10 - security risks by leaking information even
from ssl pages or from behind firewalls, the right and wrong ways to use
this field, and a problem that some sites had because of a change in
implementing this field in Microsoft IE4 (illustrating the risk of using a
field in a way it was not intended for).

Re: "Cracking DES" (Gilmore, RISKS-19.87)

Martin Minow <>
Sat, 1 Aug 1998 07:42:29 -0700
Anyone looking for a book that puts many of the "software is speech" issues
into sharp focus should get a copy of "Cracking DES: Secrets of Encryption
Research, Wiretap Politics & Chip Design" (ISBN 1-56592-520-3).  This book
describes the DES-cracking machine that was recently in the news when it
broke a 56-bit DES key in less than three days.  The bulk of the book is
also available from John Young's website, <> -- and legally
so, as the book, with a few small exceptions, is explicitly in the public
domain.  It's also available from the usual web-based booksellers.

You'll find a substantial discussion of the politics of encryption research,
the history of DES cracking, as well as all the source code and hardware
design documents.  This includes well-commented PERL and C source code
(software source code intended to be read), the VHDL code that defines the
custom chips used in the cracking engine, hardware board schematics and
design notes.  The source code is published using checksum tools that
greatly simplify the task of scanning the book to recover the original text.

While non-technical readers would not be expected to understand the computer
source code and/or hardware design, the architecture overview and the
various "political" sections should be well worth reading and within the
grasp of anyone who can get through a Scientific American article without
falling asleep.

Martin Minow,

  [Note: John Young's archive of the (legal to read) scanned volume is at
  <>.  Also, chapters that would be
  illegal to put on the Internet in the U.S. are available in abroad
  <> .]

SEI 1998 Software Engineering Symposium

Carol Biesecker <cb@SEI.CMU.EDU>
5 Aug 1998 14:59:49 GMT
SEI Software Engineering Symposium
14-17 September 1998
David L. Lawrence Convention Center
Pittsburgh, Pennsylvania
Theme: Improving What You Build Means Improving How You Build

Deadline for early bird registration discount: August 12, 1998.

For complete details, visit our Web site at:

For More Information about the Software Engineering Institute or for more
details about the Software Engineering Symposium and other events, please
contact SEI Customer Relations, 1-412-268-5800,

Please report problems with the web pages to the maintainer