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[OpenPKG-SA-2002.005] OpenPKG Security Advisory (openssh)
From: OpenPKG <openpkg () openpkg org>
Date: Wed, 26 Jun 2002 22:34:24 +0200

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________________________________________________________________________

OpenPKG Security Advisory                            The OpenPKG Project 
http://www.openpkg.org/security.html              http://www.openpkg.org
openpkg-security () openpkg org                         openpkg () openpkg org                 
OpenPKG-SA-2002.005                                          26-Jun-2002
________________________________________________________________________

Package:             openssh
Vulnerability:       DoS / remote exploit
OpenPKG Specific:    no

Affected  Releases:  OpenPKG 1.0           
Affected  Packages:  <= openssh-3.0.2p1-1.0.2
Corrected Packages:  >= openssh-3.0.2p1-1.0.3
Dependent Packages:  -                     

Description:
  According to an OpenSSH Security Advisory [5] and a corresponding
  Internet Security Systems (ISS) Security Advisory [6] there is a
  vulnerability within the "challenge-response" authentication mechanism
  in the OpenSSH daemon (sshd). This mechanism, part of the SSH2
  protocol, verifies a user's identity by generating a challenge and
  forcing the user to supply a number of responses. It is possible for
  a remote attacker to send a specially-crafted reply that triggers an
  overflow. This can result in a remote denial of service attack on the
  OpenSSH daemon or a complete remote compromise. The OpenSSH daemon
  runs with superuser privilege, so remote attackers can gain superuser
  access by exploiting this vulnerability.

  OpenSSH supports the SKEY and BSD_AUTH authentication options. These
  are compile-time options. At least one of these options must be
  enabled before the OpenSSH binaries are compiled for the vulnerable
  condition to be present. So OpenPKG's OpenSSH is *not* vulnerable
  by default, because the S/Key authentication option is disabled
  ("%define with_skey no") by default. But if users enabled this
  manually when building the OpenPKG "openssh" package, OpenPKG's
  OpenSSH is vulnerable,too.

  Please check whether you are affected by running "<prefix>/bin/rpm -qa
  openssh". If you have the "openssh" package installed and its version
  is affected (see above), we recommend that you immediately upgrade
  it (see Solution). Additionally, we recommend that you rebuild and
  reinstall all dependent OpenPKG packages, too. [2]

Solution:
  Select the updated source RPM appropriate for your OpenPKG release
  [4], fetch it from the OpenPKG FTP service [3] or a mirror location,
  verify its integrity [1], build a corresponding binary RPM from it
  and update your OpenPKG installation by applying the binary RPM [2].
  For the latest OpenPKG 1.0 release, perform the following operations
  to permanently fix the security problem (for other releases adjust
  accordingly).

  $ ftp ftp.openpkg.org
  ftp> bin
  ftp> cd release/1.0/UPD
  ftp> get openssh-3.0.2p1-1.0.3.src.rpm
  ftp> bye
  $ <prefix>/bin/rpm --checksig openssh-3.0.2p1-1.0.3.src.rpm
  $ <prefix>/bin/rpm --rebuild openssh-3.0.2p1-1.0.3.src.rpm
  $ su -
  # <prefix>/bin/rpm -Fvh <prefix>/RPM/PKG/openssh-3.0.2p1-1.0.3.*.rpm
________________________________________________________________________

References:
  [1] http://www.openpkg.org/security.html#signature
  [2] http://www.openpkg.org/tutorial.html#regular-source
  [3] ftp://ftp.openpkg.org/release/1.0/UPD/
  [4] ftp://ftp.openpkg.org/release/1.0/UPD/openssh-3.0.2p1-1.0.3.src.rpm
  [5] http://www.openssh.org/txt/preauth.adv
  [6] http://www.openssh.org/txt/iss.adv
________________________________________________________________________

For security reasons, this advisory was digitally signed with
the OpenPGP public key "OpenPKG <openpkg () openpkg org>" (ID 63C4CB9F)
of the OpenPKG project which you can find under the official URL
http://www.openpkg.org/openpkg.pgp or on http://keyserver.pgp.com/. To
check the integrity of this advisory, verify its digital signature by
using GnuPG (http://www.gnupg.org/). For instance, pipe this message to
the command "gpg --verify --keyserver keyserver.pgp.com".
________________________________________________________________________

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