[Fwd: CERT Advisory CA-2002-24 Trojan Horse OpenSSH Distribution]

Thu, 01 Aug 2002 16:33:13 -0700

In case you guys didn't get this yet.

-------- Original Message --------
Subject: CERT Advisory CA-2002-24 Trojan Horse OpenSSH Distribution
Date: Thu, 1 Aug 2002 16:45:01 -0400
From: CERT Advisory <cert-advisory@cert.org>
Organization: CERT(R) Coordination Center - +1 412-268-7090
To: cert-advisory@cert.org

-----BEGIN PGP SIGNED MESSAGE-----

CERT Advisory CA-2002-24 Trojan Horse OpenSSH Distribution

   Original issue date: August 1, 2002
   Last revised: --
   Source: CERT/CC

   A complete revision history is at the end of this file.

Overview

   The  CERT/CC  has received confirmation that some copies of the
source
   code  for the OpenSSH package were modified by an intruder and
contain
   a Trojan horse.

   We  strongly encourage sites which employ, redistribute, or mirror
the
   OpenSSH   package   to  immediately  verify  the  integrity  of 
their
   distribution.

I. Description

   The  CERT/CC  has received confirmation that some copies of the
source
   code  for  the  OpenSSH  package have been modified by an intruder
and
   contain  a  Trojan  horse. The following advisory has been released
by
   the OpenSSH development team

          http://www.openssh.com/txt/trojan.adv

   The following files were modified to include the malicious code:

     openssh-3.4p1.tar.gz
     openssh-3.4.tgz
     openssh-3.2.2p1.tar.gz

   These  files  appear to have been placed on the FTP server which
hosts
   ftp.openssh.com and ftp.openbsd.org on the 30th or 31st of July,
2002.
   The OpenSSH development team replaced the Trojan horse copies with
the
   original,  uncompromised  versions at 13:00 UTC, August 1st, 2002.
The
   Trojan  horse  copy  of  the source code was available long enough
for
   copies to propagate to sites that mirror the OpenSSH site.

   The  Trojan  horse  versions of OpenSSH contain malicious code that
is
   run  when  the  software  is  compiled.  This code connects to a
fixed
   remote  server  on  6667/tcp.  It can then open a shell running as
the
   user who compiled OpenSSH.

II. Impact

   An intruder operating from (or able to impersonate) the remote
address
   specified in the malicious code can gain unauthorized remote access
to
   any  host  which  compiled a version of OpenSSH from this Trojan
horse
   version  of  the source code. The level of access would be that of
the
   user who compiled the source code.

III. Solution

   We  encourage  sites who downloaded a copy of the OpenSSH
distribution
   to  verify the authenticity of their distribution, regardless of
where
   it  was  obtained.  Furthermore, we encourage users to inspect any
and
   all  software that may have been downloaded from the compromised
site.
   Note  that  it is not sufficient to rely on the timestamps or sizes
of
   the  file  when  trying to determine whether or not you have a copy
of
   the Trojan horse version.

Where to get OpenSSH

   The primary distribution site for OpenSSH is

          http://www.openssh.com/

   Sites that mirror the OpenSSH source code are encouraged to verify
the
   integrity of their sources.

Verify MD5 checksums

   You  can  use  the  following MD5 checksums to verify the integrity
of
   your OpenSSH source code distribution:
   Correct versions:

     459c1d0262e939d6432f193c7a4ba8a8 openssh-3.4p1.tar.gz
     d5a956263287e7fd261528bb1962f24c openssh-3.4p1.tar.gz.sig
     39659226ff5b0d16d0290b21f67c46f2 openssh-3.4.tgz
     9d3e1e31e8d6cdbfa3036cb183aa4a01 openssh-3.2.2p1.tar.gz
     be4f9ed8da1735efd770dc8fa2bb808a openssh-3.2.2p1.tar.gz.sig

   At  least  one  version of the modified Trojan horse distributions
was
   reported to have the following checksum:
   Trojan horse version:

     3ac9bc346d736b4a51d676faa2a08a57 openssh-3.4p1.tar.gz

Verify PGP signature

   Additionally,  distributions  of  the  portable release of OpenSSH
are
   distributed  with  detached PGP signatures. Note that the Trojan
horse
   versions  were  not  signed  correctly,  and  attempts  to  verify
the
   signatures would have failed.

   As a matter of good security practice, the CERT/CC encourages users
to
   verify,  whenever  possible, the integrity of downloaded software.
For
   more information, see

          http://www.cert.org/incident_notes/IN-2001-06.html

Appendix A. - Vendor Information

   This  appendix  contains  information  provided  by  vendors  for
this
   advisory.  As  vendors  report new information to the CERT/CC, we
will
   update this section and note the changes in our revision history. If
a
   particular  vendor  is  not  listed  below, we have not received
their
   comments.

Connectiva Linux

     Conectiva Linux distributes openssh-3.4p1 as a security update. The
     distributed  copy  is  the original one and is not affected by this
     trojan.  The  detached  digital  signature is always checked before
     building third party packages.

MandrakeSoft

     MandrakeSoft  has  verified  that the openssh-3.4p1 sources used to
     build  it's  latest  updates (ref. MDKSA-2002:040-1) do not contain
     this trojan.
     _________________________________________________________________
     _________________________________________________________________

   Feedback can be directed to the author: Chad Dougherty.

______________________________________________________________________

   This document is available from:
   http://www.cert.org/advisories/CA-2002-24.html

______________________________________________________________________

CERT/CC Contact Information

   Email: cert@cert.org
          Phone: +1 412-268-7090 (24-hour hotline)
          Fax: +1 412-268-6989
          Postal address:
          CERT Coordination Center
          Software Engineering Institute
          Carnegie Mellon University
          Pittsburgh PA 15213-3890
          U.S.A.

   CERT/CC   personnel   answer  the  hotline  08:00-17:00  EST(GMT-5) 
/
   EDT(GMT-4)  Monday  through  Friday;  they are on call for
emergencies
   during other hours, on U.S. holidays, and on weekends.

Using encryption

   We  strongly  urge you to encrypt sensitive information sent by
email.
   Our public PGP key is available from
   http://www.cert.org/CERT_PGP.key

   If  you  prefer  to  use  DES,  please  call the CERT hotline for
more
   information.

Getting security information

   CERT  publications  and  other security information are available
from
   our web site
   http://www.cert.org/

   To  subscribe  to  the CERT mailing list for advisories and
bulletins,
   send  email  to majordomo@cert.org. Please include in the body of
your
   message

   subscribe cert-advisory

   *  "CERT"  and  "CERT  Coordination Center" are registered in the
U.S.
   Patent and Trademark Office.

______________________________________________________________________

   NO WARRANTY
   Any  material furnished by Carnegie Mellon University and the
Software
   Engineering  Institute  is  furnished  on  an  "as is" basis.
Carnegie
   Mellon University makes no warranties of any kind, either expressed
or
   implied  as  to  any matter including, but not limited to, warranty
of
   fitness  for  a  particular purpose or merchantability, exclusivity
or
   results  obtained from use of the material. Carnegie Mellon
University
   does  not  make  any warranty of any kind with respect to freedom
from
   patent, trademark, or copyright infringement.
     _________________________________________________________________

   Conditions for use, disclaimers, and sponsorship information

   Revision History
August 1, 2002: Initial release

-----BEGIN PGP SIGNATURE-----
Version: PGP 6.5.8

iQCVAwUBPUmR3qCVPMXQI2HJAQFs7wP/SwypiZbfCb/FvMBgE3rFaY9Ul7vlyRKE
KPncunJ+KVp2sBzTbNL01wOuASx836hTa/ByXwnX4LQLX0XzBLrDcVsrDlu1pUga
Z/CopXb3KclKckmti5diCz1BNQdKbYyu/G7uHkjZQPJKC6UZr9lmge+00HMqSmHN
AAOV7PQstAc=
=FgfD
-----END PGP SIGNATURE-----