[OpenPKG-SA-2002.005] OpenPKG Security Advisory (openssh)

From: OpenPKG (openpkgat_private)
Date: Wed Jun 26 2002 - 13:34:24 PDT

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    ________________________________________________________________________
    
    OpenPKG Security Advisory                            The OpenPKG Project 
    http://www.openpkg.org/security.html              http://www.openpkg.org
    openpkg-securityat_private                         openpkgat_private                 
    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 <openpkgat_private>" (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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