752 lines
32 KiB
Plaintext
752 lines
32 KiB
Plaintext
|
|
||
|
Computer underground Digest Sun Sep 22, 1996 Volume 8 : Issue 67
|
||
|
ISSN 1004-042X
|
||
|
|
||
|
Editor: Jim Thomas (cudigest@sun.soci.niu.edu)
|
||
|
News Editor: Gordon Meyer (gmeyer@sun.soci.niu.edu)
|
||
|
Archivist: Brendan Kehoe
|
||
|
Shadow Master: Stanton McCandlish
|
||
|
Field Agent Extraordinaire: David Smith
|
||
|
Shadow-Archivists: Dan Carosone / Paul Southworth
|
||
|
Ralph Sims / Jyrki Kuoppala
|
||
|
Ian Dickinson
|
||
|
Cu Digest Homepage: http://www.soci.niu.edu/~cudigest
|
||
|
|
||
|
CONTENTS, #8.67 (Sun, Sep 22, 1996)
|
||
|
|
||
|
File 1--Hackers on Net and BBC-ISP's "morality button," from FinTimes
|
||
|
File 2--More on hackers and CIA web page
|
||
|
File 3--official statement from Lexis-Nexis about P-Trak (fwd)
|
||
|
File 4--Tim O'Reilly Comments in Re DOJ's Investigation of Microsoft
|
||
|
File 5--Condat denies the Crypt Newsletter's editor accusations
|
||
|
File 6--CERT Advisory CA-96.20 - Sendmail Vulnerabilities (fwd)
|
||
|
File 7--Cu Digest Header Info (unchanged since 7 Apr, 1996)
|
||
|
|
||
|
CuD ADMINISTRATIVE, EDITORIAL, AND SUBSCRIPTION INFORMATION ApPEARS IN
|
||
|
THE CONCLUDING FILE AT THE END OF EACH ISSUE.
|
||
|
|
||
|
---------------------------------------------------------------------
|
||
|
|
||
|
Date: Fri, 20 Sep 1996 22:36:11 -0500 (CDT)
|
||
|
From: Declan McCullagh <declan@well.com>
|
||
|
Subject: File 1--Hackers on Net and BBC-ISP's "morality button," from FinTimes
|
||
|
|
||
|
Financial Times
|
||
|
Concern at attacks by hackers on Internet sites
|
||
|
|
||
|
Wednesday September 18 1996
|
||
|
|
||
|
By Louise Kehoe in San Francisco
|
||
|
|
||
|
A rash of hacker attacks on commercial Internet sites - including one
|
||
|
in which the services of Panix, a New York-based Internet access
|
||
|
provider, were seriously disrupted - has raised new concerns about the
|
||
|
security and reliability of the worldwide computer network.
|
||
|
|
||
|
In these "denial of service" attacks, hackers have flooded Internet
|
||
|
sites with false requests for information sent from fake addresses,
|
||
|
tying up the computers and preventing access by legitimate users.
|
||
|
|
||
|
In addition to the Panix attack, at least one large information
|
||
|
technology company, which declined to be identified, has suffered a
|
||
|
similar attack.
|
||
|
|
||
|
Attacks have been "isolated incidents", said Mr Pete Solvik,
|
||
|
vice-president of information systems at Cisco Systems, the leading
|
||
|
manufacturer of routing equipment for the Internet. The company,
|
||
|
however, is concerned that the problem could spread, disrupting
|
||
|
Internet service for millions of users and effectively closing down
|
||
|
large commercial sites on the Internet.
|
||
|
|
||
|
With many banks and retailers now planning Internet services, the
|
||
|
potential for financial losses as a result of such attacks is rising.
|
||
|
Disruption of Internet service can also be a serious problem for the
|
||
|
tens of thousands of businesses that now rely on electronic mail and
|
||
|
sites on the World Wide Web to communicate with their partners and
|
||
|
|
||
|
[...]
|
||
|
|
||
|
The Federal Bureau of Investigation's New York Computer Investigations
|
||
|
Threat Assessment Center is understood to be investigating the attack
|
||
|
on Panix. Computer Emergency Response Teams, a US organisation that
|
||
|
collates information about security and technical problems on the
|
||
|
Internet, are looking into the incident.
|
||
|
|
||
|
###
|
||
|
|
||
|
Financial Times
|
||
|
BBC to enter Internet market
|
||
|
|
||
|
Thursday September 19 1996
|
||
|
|
||
|
By Alan Cane and Raymond Snoddy in London
|
||
|
|
||
|
The BBC plans to launch a service on the Internet which could promote
|
||
|
greater acceptance of the global computer network in the same way that
|
||
|
the BBC Computer popularised computing in the 1980s.
|
||
|
|
||
|
Contracts have been signed between BBC Worldwide, the public
|
||
|
broadcaster's commercial arm, and the multimedia division of ICL, the
|
||
|
UK computer group owned by Fujitsu of Japan, to design and run the
|
||
|
service.
|
||
|
|
||
|
BBC Worldwide will announce the service within the next two weeks. It
|
||
|
will feature news, weather and travel information as well as
|
||
|
educational and entertainment material. It is expected to go live in
|
||
|
the early part of 1997.
|
||
|
|
||
|
[...]
|
||
|
|
||
|
The main selling points will be speed - compared with the frequent
|
||
|
delays experienced by users - and ease of use. There will also be a
|
||
|
"morality button" to reassure parents who might fear their children
|
||
|
could use the service to view pornography and other unsuitable
|
||
|
material available on the Internet.
|
||
|
|
||
|
ICL declined to comment last night.
|
||
|
|
||
|
------------------------------
|
||
|
|
||
|
From: Declan McCullagh <declan@well.com>
|
||
|
To: fight-censorship@vorlon.mit.edu
|
||
|
Subject: File 2--More on hackers and CIA web page
|
||
|
|
||
|
The web pages are at:
|
||
|
|
||
|
http://titus.is.co.za/mikev/cia_hack/
|
||
|
http://www.skeeve.net/cia/
|
||
|
|
||
|
Looks like the hackers tipped off CNN, which has been running video clips.
|
||
|
Reuters also picked this up.
|
||
|
|
||
|
-Declan
|
||
|
|
||
|
*********
|
||
|
|
||
|
HACKERS VANDALIZE CIA HOME PAGE
|
||
|
|
||
|
No security breach of private files, agency says
|
||
|
|
||
|
September 19, 1996
|
||
|
Web posted at: 10:00 a.m. EDT (1400 GMT)
|
||
|
|
||
|
By Wayne B. Drash and Jim B. Morris
|
||
|
|
||
|
ATLANTA (CNN) -- Hackers broke into the CIA's World Wide Web home
|
||
|
page (http://www.odci.gov/cia/) Thursday morning, altered it, added
|
||
|
obscenities and changed the agency's name on the page to the
|
||
|
"Central Stupidity Agency."
|
||
|
|
||
|
The CIA, which took down the site shortly after 7:30 a.m. EDT, said
|
||
|
the hackers did not gain access to the agency's private files. "This
|
||
|
(the publicly available CIA Web site) is on an entirely different
|
||
|
circuit from everyone else at the CIA," agency spokesman Rick Oborn
|
||
|
|
||
|
He said the CIA did not know who was responsible for the hacking or
|
||
|
when the page would be restored. "A team is being pulled together to
|
||
|
assess how many layers (of the site) were affected and how we can
|
||
|
get it back on line," Oborn said.
|
||
|
|
||
|
Anonymous call
|
||
|
|
||
|
An anonymous phone caller tipped CNN Interactive to the break-in,
|
||
|
saying Swedish hackers were responsible.
|
||
|
|
||
|
The phone call was received about 5:45 a.m. EDT. When asked what the
|
||
|
hackers had done to the page, the man said, "I think you should just
|
||
|
take a look at it."
|
||
|
|
||
|
He then hung up without further comment. He did not leave his name
|
||
|
or identify a specific group.
|
||
|
|
||
|
------------------------------
|
||
|
|
||
|
Date: Wed, 18 Sep 1996 21:21:14 -0400 (EDT)
|
||
|
From: Noah <noah@enabled.com>
|
||
|
Subject: File 3--official statement from Lexis-Nexis about P-Trak (fwd)
|
||
|
|
||
|
From -Noah
|
||
|
|
||
|
---------- Forwarded message ----------
|
||
|
Date--Wed, 18 Sep 1996 21:21:14 -0400 (EDT)
|
||
|
From--Maura Kearns <zippy@mcfeely.bsfs.org>
|
||
|
|
||
|
Here's the real info on the Lexis thing:
|
||
|
|
||
|
|
||
|
This statement was issued today:
|
||
|
--------
|
||
|
STATEMENT FROM LEXIS-NEXIS 9/18/96
|
||
|
|
||
|
Incorrect information is being distributed on Internet newsgroups regarding
|
||
|
the data displayed in LEXIS-NEXIS' P-TRAK file. P-TRAK is like an
|
||
|
electronic "white pages." The only information displayed is the name of the
|
||
|
individual, current address and up to two previous addresses and telephone
|
||
|
number. In some cases, the individual's maiden name may appear and as well
|
||
|
as the month and year of birth. That is the ONLY information displayed in
|
||
|
the P-TRAK file.
|
||
|
|
||
|
Contrary to some messages that have been posted to some Internet discussion
|
||
|
and news groups, the P-TRAK file DOES NOT contain any credit histories, bank
|
||
|
account information, personal financial data, mother's maiden name or
|
||
|
medical histories. This misinformation has been posted over and over again
|
||
|
to various news groups.
|
||
|
|
||
|
An example of a record appears below:
|
||
|
|
||
|
Name: DOE, JOHN E
|
||
|
Current Address: 1066 Anywhere Drive, Dayton, OH 95454
|
||
|
Previous Address: 106 Somewhere Drive, Dayton, OH 92454
|
||
|
Birthdate: 9/1965
|
||
|
Telephone Number: 555-1212
|
||
|
On File Since: 6/1/1994
|
||
|
|
||
|
The information displayed in the P-TRAK file is the type of information
|
||
|
readily available from public information sources such as telephone
|
||
|
directories (in print and CD-ROM format) and public records maintained by
|
||
|
government agencies.
|
||
|
|
||
|
LEXIS-NEXIS markets the P-TRAK file to the legal community for use by
|
||
|
general legal practitioners, litigators and public attorneys, as well as law
|
||
|
enforcement agencies and police departments. These professionals use the
|
||
|
P-TRAK file to assist in locating litigants, witnesses, shareholders,
|
||
|
debtors, heirs and beneficiaries.
|
||
|
|
||
|
LEXIS-NEXIS is aware of the sensitivities regarding the potential misuse of
|
||
|
information. Business competitors of LEXIS-NEXIS have for some time made
|
||
|
Social Security numbers available to users of their services. In addition,
|
||
|
Social Security Numbers and other information are available on the Internet
|
||
|
from a number of sources. Despite this wide availability of Social Security
|
||
|
numbers in the market place, LEXIS-NEXIS discontinued the display of Social
|
||
|
Security numbers in the P-TRAK file as of June 11, 1996, eleven days after
|
||
|
the product was introduced.
|
||
|
|
||
|
Through its actions, LEXIS-NEXIS is balancing the privacy concerns of the
|
||
|
public with the legitimate needs of legal, business and government
|
||
|
professionals for access to accurate sources of publicly available
|
||
|
information. By discontinuing the display of Social Security numbers in
|
||
|
P-TRAK and only providing information that is already available to the
|
||
|
public from other sources, LEXIS-NEXIS believes it has responsibly met the
|
||
|
expressed concerns of the public.
|
||
|
|
||
|
Individuals interested in having their names removed from the P-TRAK file
|
||
|
can e-mail their full name and complete address to:
|
||
|
p-trak@prod.lexis-nexis.com or mail this information to ATTN: P-TRAK, P. O.
|
||
|
Box 933, Dayton, OH 45401.
|
||
|
|
||
|
------------------------------
|
||
|
|
||
|
Date: Thu, 19 Sep 1996 19:00:41 -0700
|
||
|
From: Ellen Elias <elias@ora.com>
|
||
|
Subject: File 4--Tim O'Reilly Comments in Re DOJ's Investigation of Microsoft
|
||
|
|
||
|
For Immediate Release
|
||
|
Further Information Contact
|
||
|
Ellen Elias
|
||
|
(707)829-0515 ext. 322
|
||
|
elias@ora.com
|
||
|
|
||
|
STATEMENT OF TIM O'REILLY, PRESIDENT OF O'REILLY & ASSOCIATES, IN
|
||
|
RESPONSE TO CONFIRMATION OF JUSTICE DEPARTMENT'S INVESTIGATION OF
|
||
|
MICROSOFT
|
||
|
|
||
|
September 19, 1996, Sebastopol, CA--Tim O'Reilly, upon learning of the
|
||
|
confirmed investigation of Microsoft by the federal Department of
|
||
|
Justice, called for Microsoft to cease its anti-competitive behavior.
|
||
|
Mr. O'Reilly made the following comments:
|
||
|
|
||
|
"I'm delighted to hear about the Department of Justice
|
||
|
investigation. We don't know what they'll find, but we do know
|
||
|
that Microsoft's recent practices have been bad for users, and
|
||
|
they have demonstrated a pattern of anti-competitive behavior.
|
||
|
The fact of this investigation will further alert people to
|
||
|
Microsoft's activities. I believe in the marketplace, and think
|
||
|
that there can be a healthy impact on the marketplace from the
|
||
|
DOJ investigation.
|
||
|
|
||
|
"Each time O'Reilly & Associates has brought a particular fact about
|
||
|
Microsoft into the public eye, the response from Microsoft has been
|
||
|
deceptive and confusing. In July, 1996, we complained publicly about
|
||
|
their 10-connection limit on Windows NT Workstation. In response,
|
||
|
Microsoft removed the 10-connection limit from the code, but then kept
|
||
|
it in the user license. Further, Microsoft made extravagant claims that
|
||
|
they were doing this for users: they claimed that NT Workstation was
|
||
|
just not suitable as a Web server platform. That claim inspired our
|
||
|
Senior Editor Andrew Schulman's investigation into the actual
|
||
|
differences between NT Workstation and NT Server. He found that,
|
||
|
indeed, at the core, they are not very different at all.
|
||
|
|
||
|
"Microsoft doesn't need to win every battle to stifle innovation. As
|
||
|
powerful as they are, they can determine the terms under which software
|
||
|
development happens, and they can seriously limit important development
|
||
|
by their anti-competitive behavior. Here's an example: when O'Reilly &
|
||
|
Associates first developed and marketed WebSite(TM), Microsoft patted
|
||
|
us on the back, because we were legitimizing NT as a Web server
|
||
|
platform. But when Microsoft decided they wanted the Web server market
|
||
|
for themselves, they used their restrictive NT 4.0 Workstation user
|
||
|
license as a tool to frighten users against using any competitors' Web
|
||
|
servers on that platform. Microsoft's actions have made it difficult
|
||
|
for us, as well as all other server vendors, to compete. So what kind
|
||
|
of industry does that create?
|
||
|
|
||
|
"Netscape has claimed that many people have been afraid to speak in
|
||
|
fear of retribution from Microsoft. Netscape has said that now, these
|
||
|
people will feel free to speak publicly, and I think that should prove
|
||
|
very enlightening. I hope the Department of Justice will vigorously
|
||
|
pursue this investigation. I also hope the public will hold Microsoft
|
||
|
to the same high standard of business practices to which our entire
|
||
|
industry should adhere."
|
||
|
|
||
|
------------------------------
|
||
|
|
||
|
Date: Wed, 18 Sep 1996 15:12:31 +0100
|
||
|
From: Jean-Bernard Condat <jeanbc@INFORMIX.COM>
|
||
|
Subject: File 5--Condat denies the Crypt Newsletter's editor accusations
|
||
|
|
||
|
This morning, I receive the Cu Digest #8.66 and carefully read the
|
||
|
file 3 with a complete surprise. I never send any article related to
|
||
|
computer viruses troubles during the US Army's Bosnian deployment
|
||
|
plagiarizing the well-knowned Crypt Newsletter.
|
||
|
|
||
|
After my publication of the Mark A. Ludwig's book "The Little Black
|
||
|
Book of Computer Viruses" with Addison-Wesley France ("Naissance
|
||
|
d'un virus" for the first volume and "Mutation d'un virus" for the
|
||
|
second one), I have had a lot of problems: night & day phone calls,
|
||
|
injures, public critics on French TV and/or magazines, etc. I stop
|
||
|
the crazy rumors immediately. I don't writte any more computer
|
||
|
virus' articles; I don't participate to any security events; I don't
|
||
|
collaborate to any craking/phreaking/swapping actions. For example,
|
||
|
I don't participate to the French 2600 meeting in Porte d'Italie in
|
||
|
Paris last week.
|
||
|
|
||
|
As my understanding, this previous email under my name was send to
|
||
|
CuD editors from and unauthorized source. As some of you know, I
|
||
|
have been having problems with the secret services in the past and I
|
||
|
got into a large battle with was France Telecom -vs- Me. It is
|
||
|
stupid to get into an argument with that kind of corporation, and a
|
||
|
few words and threats were thrown, they locked all my phone
|
||
|
accounts. I wrote a letter in response of that and they proceded to
|
||
|
harass my company that put me immediately out. Also some lamers
|
||
|
posted some hoax letters in the French news groups and whatever.
|
||
|
They eventually decided to charge me and whatever, and to save me
|
||
|
time outta the Paris courts and crap like that I made an apology for
|
||
|
the threats, seeing that they could incriminate me. France Telecom
|
||
|
has done wrong and I probably won't be seeing alot of apologies
|
||
|
coming my way. If they didn't have certain info about me... they
|
||
|
could have me very well laughing at them but that is not the case.
|
||
|
|
||
|
At this time, I have some crazy guys that don't hesitate to put all
|
||
|
the scripts of my TV shows
|
||
|
(http://www.magic.be/InterieurNuit/SiteMars/Condat.html), or to put
|
||
|
my picture (http://www.condat.de/condat/jean-b/). Yesterday, I lost
|
||
|
my job of senior consultant in the Smart Card Business Unit of
|
||
|
Informix because Mr. Tariq Krim of the ENST in Paris don't hesitate
|
||
|
to call all my chiefs with some kind words on my life. In France,
|
||
|
this type of action permit to put me out the company some seconds
|
||
|
after.
|
||
|
|
||
|
"Information wants to be free" is false. I have to many subjects to
|
||
|
writte on that to plagiarized Crypt News will be a "sincerest form
|
||
|
of flattery", like George Smith writte. But I prefer the unpolically
|
||
|
correct French-style-approach, the savoir-vivre of Paris. Accept all
|
||
|
my real excuses for all the French guy like Krim that prefer to
|
||
|
crash my career for having the pleasure to be the best! I read Crypt
|
||
|
News with pleasure and always respect the international copyright
|
||
|
notices.
|
||
|
|
||
|
Apologetically,
|
||
|
|
||
|
\\\|///
|
||
|
| ~ ~ |
|
||
|
(- 0 0 -)
|
||
|
+--------------------.oOOo-(_)-oOOo.-------------------------+
|
||
|
| Jean-Bernard Condat |
|
||
|
| 47 rue des rosiers, 93400 Saint-Ouen France |
|
||
|
| Phone: +33 1 40100357, fax: 1 46963765, Itineris: 07238628 |
|
||
|
| Email: condat@atelier.fr, PGP Key Id: C8F5D50D |
|
||
|
| Oooo. |
|
||
|
+--------------------.oooO-----( )--------------------------+
|
||
|
( ) ) /
|
||
|
\ ( (_/
|
||
|
\_)
|
||
|
|
||
|
------------------------------
|
||
|
|
||
|
Date: Wed, 18 Sep 1996 10:40:07 -0400
|
||
|
From: Noah <noah@enabled.com>
|
||
|
Subject: File 6--CERT Advisory CA-96.20 - Sendmail Vulnerabilities (fwd)
|
||
|
|
||
|
From -Noah
|
||
|
|
||
|
---------- Forwarded message ----------
|
||
|
Date--Wed, 18 Sep 1996 10:40:07 -0400
|
||
|
From--CERT Advisory <cert-advisory@cert.org>
|
||
|
|
||
|
-----BEGIN PGP SIGNED MESSAGE-----
|
||
|
|
||
|
=============================================================================
|
||
|
CERT(sm) Advisory CA-96.20
|
||
|
Original issue date: September 18, 1996
|
||
|
Last revised: --
|
||
|
|
||
|
Topic: Sendmail Vulnerabilities
|
||
|
- -----------------------------------------------------------------------------
|
||
|
*** This advisory supersedes CA-95:05 ***
|
||
|
|
||
|
The CERT Coordination Center has received reports of two security problems in
|
||
|
sendmail that affect all versions up to and including 8.7.5. By exploiting
|
||
|
the first of these vulnerabilities, users who have local accounts can gain
|
||
|
access to the default user, which is often daemon. By exploiting the second
|
||
|
vulnerability, any local user can gain root access.
|
||
|
|
||
|
The CERT/CC team recommends installing vendor patches or upgrading to the
|
||
|
current version of sendmail (8.7.6). Until you can do so, we urge you to
|
||
|
apply the workaround provided in Sec. III.C. In all cases, be sure to take
|
||
|
the extra precautions listed in Sec. III.D.
|
||
|
|
||
|
For beta testers of sendmail 8.8: The vulnerabilities described in this
|
||
|
advisory have been fixed in the beta version.
|
||
|
|
||
|
We will update this advisory as we receive additional information. Please
|
||
|
check advisory files regularly for updates that relate to your site. In
|
||
|
addition, you can check ftp://info.cert.org/pub/latest_sw_versions/sendmail
|
||
|
to identify the most current version of sendmail.
|
||
|
|
||
|
- -----------------------------------------------------------------------------
|
||
|
|
||
|
I. Description
|
||
|
|
||
|
There are two vulnerabilities in all versions of sendmail up to and
|
||
|
including sendmail 8.7.5. The first vulnerability is a resource starvation
|
||
|
problem and the second is a buffer overflow problem.
|
||
|
|
||
|
Resource Starvation
|
||
|
-------------------
|
||
|
|
||
|
When email is forwarded to a program using a .forward file or an :include:
|
||
|
statement within a .forward or alias file, that program is executed as the
|
||
|
owner of the .forward file or the file referenced by the :include:
|
||
|
statement. Similarly, if email is forwarded to a file, that file is
|
||
|
opened as the owner of the .forward file or the file referenced by the
|
||
|
:include: statement. The file owner is called the "controlling user."
|
||
|
|
||
|
If the message cannot be delivered immediately, the name of the
|
||
|
controlling user is written into the queue file along with the other
|
||
|
delivery information so that the appropriate permissions can be acquired
|
||
|
when the mail queue is processed.
|
||
|
|
||
|
Only the name of the controlling user is written in the queue file. This
|
||
|
name is derived by calling the system routine getpwuid(3) on the user id
|
||
|
of the file owner. If getpwuid fails, the sendmail default user (defined
|
||
|
by the DefaultUser option in 8.7 and by the "u" and "g" options in older
|
||
|
releases) is assumed.
|
||
|
|
||
|
In some cases, the system can be forced into resource starvation, thus
|
||
|
forcing getpwuid(3) to fail even though an entry exists in /etc/passwd
|
||
|
corresponding to that uid. Since getpwuid has no way of portably
|
||
|
returning an error meaning "resource failure" as distinct from "user id
|
||
|
not found," sendmail has no way of distinguishing between these cases; it
|
||
|
assumes that the uid is unknown and falls back to the default user.
|
||
|
|
||
|
By starving sendmail of specific resources, sendmail will create files
|
||
|
owned by the default user. Once created, these files can be used to
|
||
|
access other files owned by the default user. In addition, these files
|
||
|
owned by the default user can be used to leverage access to other
|
||
|
privileged users on the system.
|
||
|
|
||
|
Buffer Overflows
|
||
|
----------------
|
||
|
There are several buffer overflows present in sendmail version 8.7.5 and
|
||
|
earlier. Some of the buffer overflows could result in local users gaining
|
||
|
unauthorized root access.
|
||
|
|
||
|
Significant work has been done on sendmail version 8.8 (now in beta
|
||
|
test) to eliminate the problem, and the code changes originally planned
|
||
|
for 8.8 have been backported to 8.7.6 to address these vulnerabilities.
|
||
|
|
||
|
II. Impact
|
||
|
|
||
|
Resource Starvation
|
||
|
-------------------
|
||
|
Anyone with access to an account on the system can run programs or write
|
||
|
files as the default user. The danger of compromising the default user
|
||
|
depends primarily on the other files in your system owned by that user.
|
||
|
|
||
|
For example, on many systems the line printer spool directory (e.g.,
|
||
|
/var/spool/lpd) is owned by daemon; because the line printer subsystem
|
||
|
runs setuid root, it may be possible to gain additional privileges.
|
||
|
However, some other systems have no files owned by user daemon on the
|
||
|
default system, and the only files owned by group daemon are not
|
||
|
writable by that group; hence, the danger is minimal.
|
||
|
|
||
|
Buffer Overflows
|
||
|
----------------
|
||
|
Anyone with access to an account on the system can gain root access.
|
||
|
|
||
|
III. Solution
|
||
|
|
||
|
Install a patch from your vendor if one is available (Sec. A) or upgrade
|
||
|
to the current version of sendmail (Sec. B). Until you can take one of
|
||
|
those actions, we recommend applying the workaround described in Sec. C.
|
||
|
This workaround addresses the resource starvation problem but not buffer
|
||
|
overflows.
|
||
|
|
||
|
In all cases, you should take the precautions listed in Sec. D.
|
||
|
|
||
|
Note to beta testers of sendmail 8.8: The vulnerabilities described in
|
||
|
this advisory have been fixed in the beta version of 8.8.
|
||
|
|
||
|
A. Install a vendor patch.
|
||
|
|
||
|
Below is a list of the vendors who have provided information about
|
||
|
sendmail. Details are in Appendix A of this advisory; we will update
|
||
|
the appendix as we receive more information. If your vendor's name
|
||
|
is not on this list, please contact the vendor directly.
|
||
|
|
||
|
Digital Equipment Corporation
|
||
|
Hewlett-Packard Company
|
||
|
IBM Corporation
|
||
|
Linux
|
||
|
Open Software Foundation
|
||
|
The Santa Cruz Operation
|
||
|
Silicon Graphics Inc.
|
||
|
Sun Microsystems, Inc.
|
||
|
|
||
|
B. Upgrade to the current version of sendmail.
|
||
|
|
||
|
Install sendmail 8.7.6. This version is a "drop in" replacement for
|
||
|
8.7.x. There is no patch for 8.6.x. If you are using version 8.6 or
|
||
|
earlier, you need to upgrade to the current version and rebuild your
|
||
|
sendmail.cf files. Upgrading to version 8.7.6 addresses both
|
||
|
vulnerabilities described in this advisory.
|
||
|
|
||
|
Sendmail 8.7.6 is available from
|
||
|
|
||
|
ftp://ftp.sendmail.org/ucb/src/sendmail/sendmail.8.7.6.tar.gz
|
||
|
ftp://info.cert.org/pub/tools/sendmail/sendmail.8.7.6.tar.gz
|
||
|
ftp://ftp.cert.dfn.de/pub/tools/net/sendmail/sendmail.8.7.6.tar.gz
|
||
|
|
||
|
MD5 (sendmail.8.7.6.tar.gz) = 4a1f2179c53c9106bc8d7738f4d55667
|
||
|
|
||
|
Also in that directory are .Z and .sig files. The .Z file contains the
|
||
|
same bits as the .gz file, but is compressed using UNIX compress
|
||
|
instead of gzip. The .sig is Eric Allman's PGP signature for the
|
||
|
uncompressed tar file. The key fingerprint is
|
||
|
|
||
|
Type bits/keyID Date User ID
|
||
|
pub 1024/BF7BA421 1995/02/23 Eric P. Allman <eric@CS.Berkeley.EDU>
|
||
|
Key fingerprint = C0 28 E6 7B 13 5B 29 02 6F 7E 43 3A 48 4F 45 29
|
||
|
Eric P. Allman <eric@Reference.COM>
|
||
|
Eric P. Allman <eric@Usenix.ORG>
|
||
|
Eric P. Allman <eric@Sendmail.ORG>
|
||
|
Eric P. Allman <eric@CS.Berkeley.EDU>
|
||
|
|
||
|
We strongly recommend that when you change to a new version of sendmail
|
||
|
you also change to the configuration files that are provided with that
|
||
|
version.
|
||
|
|
||
|
Significant work has been done to make this task easier. It is now
|
||
|
possible to build a sendmail configuration file (sendmail.cf) using the
|
||
|
configuration files provided with the sendmail release. Consult the
|
||
|
cf/README file for a more complete explanation. Creating your
|
||
|
configuration files using this method makes it easier to incorporate
|
||
|
future changes to sendmail into your configuration files.
|
||
|
|
||
|
Finally, for Sun users, a paper is available to help you convert your
|
||
|
sendmail configuration files from the Sun version of sendmail to one
|
||
|
that works with sendmail version 8.7.x. The paper is entitled
|
||
|
"Converting Standard Sun Config Files to Sendmail Version 8" and was
|
||
|
written by Rick McCarty of Texas Instruments Inc. It is included in
|
||
|
the distribution and is located in contrib/converting.sun.configs.
|
||
|
|
||
|
C. Apply a workaround.
|
||
|
|
||
|
Resource Starvation
|
||
|
-------------------
|
||
|
Eric Allman, the author of sendmail, has provided the following
|
||
|
workaround to the resource starvation vulnerability.
|
||
|
|
||
|
Using smrsh as "prog" mailer limits the programs that can be run as
|
||
|
the default user. Smrsh does not limit the files that can be written,
|
||
|
but less damage can be done by writing files directly.
|
||
|
|
||
|
The damage can be almost entirely constrained by ensuring that the
|
||
|
default user is an innocuous one. Sendmail defaults to 1:1 (daemon)
|
||
|
only because that is reasonably portable. A special "mailnull"
|
||
|
account that is used only for this purpose would be better. This user
|
||
|
should own no files and should have neither a real home directory nor
|
||
|
a real shell. A sample password entry might be:
|
||
|
|
||
|
mailnull:*:32765:32765:Sendmail Default User:/no/such/dir:/dev/null
|
||
|
|
||
|
A corresponding entry should be made in /etc/group:
|
||
|
|
||
|
mailnull:*:32765:
|
||
|
|
||
|
These assume that there are no other users or groups with id = 32765
|
||
|
on your system; if there are, pick some other unique value. After
|
||
|
creating this user, change the line in /etc/sendmail.cf reading
|
||
|
|
||
|
O DefaultUser=1:1
|
||
|
|
||
|
to read
|
||
|
|
||
|
O DefaultUser=mailnull
|
||
|
|
||
|
If you are running 8.6.*, you will have to change the lines reading
|
||
|
|
||
|
Ou1
|
||
|
Og1
|
||
|
|
||
|
to read
|
||
|
|
||
|
Ou32765
|
||
|
Og32765
|
||
|
|
||
|
Finally, if you are using the m4(1)-based sendmail configuration scheme
|
||
|
provided with sendmail 8.7.*, you should add the following line to the
|
||
|
m4 input file, usually named sendmail.mc:
|
||
|
|
||
|
define(`confDEF_USER_ID', 32765:32765)
|
||
|
|
||
|
The actual values should, of course, match those in the passwd file.
|
||
|
|
||
|
Buffer Overflows
|
||
|
----------------
|
||
|
There is no workaround for the buffer overflow problem. To address this
|
||
|
problem, you must apply your vendor's patches or upgrade to the current
|
||
|
version of sendmail (version 8.7.6).
|
||
|
|
||
|
D. Take additional precautions.
|
||
|
|
||
|
Regardless of which solution you apply, you should take these extra
|
||
|
precautions to protect your systems.
|
||
|
|
||
|
* Use the sendmail restricted shell program (smrsh)
|
||
|
|
||
|
With *all* versions of sendmail, use the sendmail restricted shell
|
||
|
program (smrsh). You should do this whether you use vendor-supplied
|
||
|
sendmail or install sendmail yourself. Using smrsh gives you improved
|
||
|
administrative control over the programs sendmail executes on behalf of
|
||
|
users.
|
||
|
|
||
|
A number of sites have reported some confusion about the need to continue
|
||
|
using the sendmail restricted shell program (smrsh) when they install a
|
||
|
vendor patch or upgrade to a new version of sendmail. You should always
|
||
|
use the smrsh program.
|
||
|
|
||
|
smrsh is included in the sendmail distribution in the subdirectory
|
||
|
smrsh. See the RELEASE_NOTES file for a description of how to integrate
|
||
|
smrsh into your sendmail configuration file.
|
||
|
|
||
|
smrsh is also distributed with some operating systems.
|
||
|
|
||
|
* Use mail.local
|
||
|
|
||
|
If you run /bin/mail based on BSD 4.3 UNIX, replace /bin/mail with
|
||
|
mail.local, which is included in the sendmail distribution. It is also
|
||
|
included with some other operating systems distributions, such as
|
||
|
FreeBSD.
|
||
|
|
||
|
Although the current version of mail.local is not a perfect solution, it
|
||
|
is important to use it because it addresses vulnerabilities that are
|
||
|
being exploited. For more details, see CERT advisory CA-95:02.
|
||
|
|
||
|
Note that as of Solaris 2.5 and beyond, mail.local is included with the
|
||
|
standard distribution. To use mail.local, replace all references to
|
||
|
/bin/mail with /usr/lib/mail.local. If you are using the M4(1)-based
|
||
|
configuration scheme provided with sendmail 8.X, add the following to
|
||
|
your configuration file:
|
||
|
|
||
|
define(`LOCAL_MAILER_PATH', /usr/lib/mail.local)
|
||
|
|
||
|
* WARNING: Check for executable copies of old versions of mail programs
|
||
|
|
||
|
If you leave executable copies of older versions of sendmail installed
|
||
|
in /usr/lib (on some systems, it may be installed elsewhere), the
|
||
|
vulnerabilities in those versions could be exploited if an intruder
|
||
|
gains access to your system. This applies to sendmail.mx as well as
|
||
|
other sendmail programs. Either delete these versions or change the
|
||
|
protections on them to be non-executable.
|
||
|
|
||
|
Similarly, if you replace /bin/mail with mail.local, remember to remove
|
||
|
old copies of /bin/mail or make them non-executable.
|
||
|
|
||
|
<snip>
|
||
|
|
||
|
------------------------------
|
||
|
|
||
|
Date: Thu, 21 Mar 1996 22:51:01 CST
|
||
|
From: CuD Moderators <cudigest@sun.soci.niu.edu>
|
||
|
Subject: File 7--Cu Digest Header Info (unchanged since 7 Apr, 1996)
|
||
|
|
||
|
Cu-Digest is a weekly electronic journal/newsletter. Subscriptions are
|
||
|
available at no cost electronically.
|
||
|
|
||
|
CuD is available as a Usenet newsgroup: comp.society.cu-digest
|
||
|
|
||
|
Or, to subscribe, send post with this in the "Subject:: line:
|
||
|
|
||
|
SUBSCRIBE CU-DIGEST
|
||
|
Send the message to: cu-digest-request@weber.ucsd.edu
|
||
|
|
||
|
DO NOT SEND SUBSCRIPTIONS TO THE MODERATORS.
|
||
|
|
||
|
The editors may be contacted by voice (815-753-0303), fax (815-753-6302)
|
||
|
or U.S. mail at: Jim Thomas, Department of Sociology, NIU, DeKalb, IL
|
||
|
60115, USA.
|
||
|
|
||
|
To UNSUB, send a one-line message: UNSUB CU-DIGEST
|
||
|
Send it to CU-DIGEST-REQUEST@WEBER.UCSD.EDU
|
||
|
(NOTE: The address you unsub must correspond to your From: line)
|
||
|
|
||
|
Issues of CuD can also be found in the Usenet comp.society.cu-digest
|
||
|
news group; on CompuServe in DL0 and DL4 of the IBMBBS SIG, DL1 of
|
||
|
LAWSIG, and DL1 of TELECOM; on GEnie in the PF*NPC RT
|
||
|
libraries and in the VIRUS/SECURITY library; from America Online in
|
||
|
the PC Telecom forum under "computing newsletters;"
|
||
|
On Delphi in the General Discussion database of the Internet SIG;
|
||
|
on RIPCO BBS (312) 528-5020 (and via Ripco on internet);
|
||
|
and on Rune Stone BBS (IIRGWHQ) (860)-585-9638.
|
||
|
CuD is also available via Fidonet File Request from
|
||
|
1:11/70; unlisted nodes and points welcome.
|
||
|
|
||
|
EUROPE: In BELGIUM: Virtual Access BBS: +32-69-844-019 (ringdown)
|
||
|
In ITALY: ZERO! BBS: +39-11-6507540
|
||
|
In LUXEMBOURG: ComNet BBS: +352-466893
|
||
|
|
||
|
UNITED STATES: etext.archive.umich.edu (192.131.22.8) in /pub/CuD/CuD
|
||
|
ftp.eff.org (192.88.144.4) in /pub/Publications/CuD/
|
||
|
aql.gatech.edu (128.61.10.53) in /pub/eff/cud/
|
||
|
world.std.com in /src/wuarchive/doc/EFF/Publications/CuD/
|
||
|
wuarchive.wustl.edu in /doc/EFF/Publications/CuD/
|
||
|
EUROPE: nic.funet.fi in pub/doc/CuD/CuD/ (Finland)
|
||
|
ftp.warwick.ac.uk in pub/cud/ (United Kingdom)
|
||
|
|
||
|
|
||
|
The most recent issues of CuD can be obtained from the
|
||
|
Cu Digest WWW site at:
|
||
|
URL: http://www.soci.niu.edu/~cudigest/
|
||
|
|
||
|
COMPUTER UNDERGROUND DIGEST is an open forum dedicated to sharing
|
||
|
information among computerists and to the presentation and debate of
|
||
|
diverse views. CuD material may be reprinted for non-profit as long
|
||
|
as the source is cited. Authors hold a presumptive copyright, and
|
||
|
they should be contacted for reprint permission. It is assumed that
|
||
|
non-personal mail to the moderators may be reprinted unless otherwise
|
||
|
specified. Readers are encouraged to submit reasoned articles
|
||
|
relating to computer culture and communication. Articles are
|
||
|
preferred to short responses. Please avoid quoting previous posts
|
||
|
unless absolutely necessary.
|
||
|
|
||
|
DISCLAIMER: The views represented herein do not necessarily represent
|
||
|
the views of the moderators. Digest contributors assume all
|
||
|
responsibility for ensuring that articles submitted do not
|
||
|
violate copyright protections.
|
||
|
|
||
|
------------------------------
|
||
|
|
||
|
End of Computer Underground Digest #8.67
|
||
|
************************************
|
||
|
|