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[CLA-2002:500] Conectiva Linux Security Announcement - openssh
From: secure () conectiva com br
Date: Tue, 25 Jun 2002 17:13:44 -0300

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CONECTIVA LINUX SECURITY ANNOUNCEMENT 
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PACKAGE   : openssh
SUMMARY   : Remote vulnerability in OpenSSH
DATE      : 2002-06-25 17:12:00
ID        : CLA-2002:500
RELEVANT
RELEASES  : 6.0, 7.0, 8

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DESCRIPTION
 OpenSSH[1] is a very popular and versatile tool that uses encrypted
 connections between hosts and is commonly used for remote
 administration.
 
 The OpenSSH development teem announced[2] that there is a serious
 remote vulnerability in this service and that there is no fix for
 this problem at this time. No further details have been released
 about the vulnerability.
 
 OpenSSH 3.3, however, implements by default a new feature called
 "PrivilegeSeparation" that, according to the authors, prevents this
 and future vulnerabilities, or at least mitigates their impact
 severely. The OpenSSH team is strongly recommending that, even though
 this version does not fix the issue, all users upgrade as soon as
 possible due to this new security feature.
 
 The PrivilegeSeparation[6] feature creates a new "sshd" process that
 handles the network traffic and interacts with the remote user. This
 process is unprivileged, running under an "sshd" userid and chrooted
 in an emtpy directory called /var/emtpy.
 
 This is a new feature of OpenSSH and there are some pending issues
 (specially regarding PAM) that are being addressed:
 - authentication via KeyboardInteractive does not work with
 PrivilegeSeparation yet. This affects, for example, Kerberos5 logins
 with the SSH1 protocol;
 - by default data compression ("UseCompression yes" in sshd_config)
 cannot be used with PrivilegeSeparation in 2.2 kernels. The packages
 provided with this update, though, have a patch done by Solar
 Designer (developer from the Openwall[4] project) to address this and
 allow compression and PrivilegeSeparation in 2.2 kernels. But this
 issue is still being addressed by the OpenSSH developers.
 - expired passwords do not work with PrivilegeSeparation yet.
 Previously the user got the chance to change his/her expired password
 after logging in. With PrivilegeSeparation, the user is instantly
 denied access if his/her password has expired.
 
 Again, it is important to note that the 3.3p1 version still has a
 vulnerability, but that the use of PrivilegeSeparation greatly
 mitigates its impact and is therefore a recommended upgrade.
 
 The OpenSSH team is working hard to address these remaining issues
 with PrivilegeSeparation on several platforms, including GNU/Linux,
 and also in fixing the vulnerability. There will be other releases in
 the following days. In the meantime, the use of PrivilegeSeparation
 in this new OpenSSH release is strongly recommended.


SOLUTION
 It is recommended that all OpenSSH users upgrade their packages. The
 sshd service will be restarted automatically if it is already running
 before the upgrade.
 
 It has been verified, however, that the service restart command
 issued during the upgrade keeps an open file descriptor if done
 remotely, which will keep the terminal open even after logout (also
 known as "hang on exit" problem). Therefore, we recommend that a
 manual "/sbin/service sshd restart" command be issued if the upgrade
 is being done remotely to prevent this behaviour. We are still
 investigating the issue.
 
 
 REFERENCES
 1.http://www.openssh.com
 2.http://marc.theaimsgroup.com/?l=openssh-unix-dev&m=102495293705094&w=2
 3.http://lwn.net/Vulnerabilities/3290/
 4.http://www.openwall.com/Owl/
 5.http://distro.conectiva.com.br/pipermail/seguranca/2002-June/002864.html
 6.http://www.citi.umich.edu/u/provos/ssh/privsep.html


DIRECT DOWNLOAD LINKS TO THE UPDATED PACKAGES
ftp://atualizacoes.conectiva.com.br/6.0/SRPMS/openssh-3.3p1-1U60_1cl.src.rpm
ftp://atualizacoes.conectiva.com.br/6.0/RPMS/openssh-3.3p1-1U60_1cl.i386.rpm
ftp://atualizacoes.conectiva.com.br/6.0/RPMS/openssh-askpass-3.3p1-1U60_1cl.i386.rpm
ftp://atualizacoes.conectiva.com.br/6.0/RPMS/openssh-askpass-gnome-3.3p1-1U60_1cl.i386.rpm
ftp://atualizacoes.conectiva.com.br/6.0/RPMS/openssh-clients-3.3p1-1U60_1cl.i386.rpm
ftp://atualizacoes.conectiva.com.br/6.0/RPMS/openssh-server-3.3p1-1U60_1cl.i386.rpm
ftp://atualizacoes.conectiva.com.br/7.0/SRPMS/openssh-3.3p1-1U70_1cl.src.rpm
ftp://atualizacoes.conectiva.com.br/7.0/RPMS/openssh-3.3p1-1U70_1cl.i386.rpm
ftp://atualizacoes.conectiva.com.br/7.0/RPMS/openssh-askpass-3.3p1-1U70_1cl.i386.rpm
ftp://atualizacoes.conectiva.com.br/7.0/RPMS/openssh-askpass-gnome-3.3p1-1U70_1cl.i386.rpm
ftp://atualizacoes.conectiva.com.br/7.0/RPMS/openssh-clients-3.3p1-1U70_1cl.i386.rpm
ftp://atualizacoes.conectiva.com.br/7.0/RPMS/openssh-server-3.3p1-1U70_1cl.i386.rpm
ftp://atualizacoes.conectiva.com.br/8/SRPMS/openssh-3.3p1-1U8_1cl.src.rpm
ftp://atualizacoes.conectiva.com.br/8/RPMS/openssh-3.3p1-1U8_1cl.i386.rpm
ftp://atualizacoes.conectiva.com.br/8/RPMS/openssh-askpass-3.3p1-1U8_1cl.i386.rpm
ftp://atualizacoes.conectiva.com.br/8/RPMS/openssh-askpass-gnome-3.3p1-1U8_1cl.i386.rpm
ftp://atualizacoes.conectiva.com.br/8/RPMS/openssh-clients-3.3p1-1U8_1cl.i386.rpm
ftp://atualizacoes.conectiva.com.br/8/RPMS/openssh-server-3.3p1-1U8_1cl.i386.rpm


ADDITIONAL INSTRUCTIONS
 Users of Conectiva Linux version 6.0 or higher may use apt to perform 
 upgrades of RPM packages:
 - add the following line to /etc/apt/sources.list if it is not there yet
   (you may also use linuxconf to do this):

 rpm [cncbr] ftp://atualizacoes.conectiva.com.br 6.0/conectiva updates

(replace 6.0 with the correct version number if you are not running CL6.0)

 - run:                 apt-get update
 - after that, execute: apt-get upgrade

 Detailed instructions reagarding the use of apt and upgrade examples 
 can be found at http://distro.conectiva.com.br/atualizacoes/#apt?idioma=en


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All packages are signed with Conectiva's GPG key. The key and instructions
on how to import it can be found at 
http://distro.conectiva.com.br/seguranca/chave/?idioma=en
Instructions on how to check the signatures of the RPM packages can be
found at http://distro.conectiva.com.br/seguranca/politica/?idioma=en
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All our advisories and generic update instructions can be viewed at
http://distro.conectiva.com.br/atualizacoes/?idioma=en

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