[OpenPKG-SA-2003.035] OpenPKG Security Advisory (openssh)

[OpenPKG <openpkg () openpkg org>]

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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-2003.035                                          06-Aug-2003
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Package:             openssh
Vulnerability:       information leakage
OpenPKG Specific:    no

Affected Releases:   Affected Packages:          Corrected Packages:
OpenPKG CURRENT      <= openssh-3.6.1p1-20030423 >= openssh-3.6.1p2-20030429
OpenPKG 1.3          none                        N.A.
OpenPKG 1.2          <= openssh-3.5p1-1.2.1      >= openssh-3.5p1-1.2.2

Dependent Packages:  none

Description:
  According to a Mediaservice.net security advisory [0], an information
  leakage exists in OpenSSH [1] 3.6.1p1 and earlier if PAM support
  is enabled. When a user does not exists, an error message is sent
  immediately (without any delays) which allows remote attackers to
  determine valid usernames via a timing attack. OpenPKG installations
  are only affected if the package was build with option "with_pam"
  set to "yes" -- which is not the default. The Common Vulnerabilities
  and Exposures (CVE) project assigned the id CAN-2003-0190 [2] to the
  problem.
  
  We could only reproduce the problem on Linux. FreeBSD and Solaris are
  not vulnerable, the patch does not affect their behaviour. However,
  the problem is related to the PAM configuration, not the operating
  system. Using a non-default configuration might leak information on
  other operating systems, too. On Linux systems, a valid workaround is
  to add a "nodelay" option to the pam_unix.so auth.

  Please check whether you are affected by running "<prefix>/bin/rpm -q
  openssh". If you have the "openssh" package installed and its version
  is affected (see above), we recommend that you immediately upgrade it
  (see Solution).

Solution:
  Select the updated source RPM appropriate for your OpenPKG release
  [5], fetch it from the OpenPKG FTP service [6] or a mirror location,
  verify its integrity [7], build a corresponding binary RPM from it [3]
  and update your OpenPKG installation by applying the binary RPM [4].
  For the current release OpenPKG 1.2, perform the following operations
  to permanently fix the security problem (for other releases adjust
  accordingly).

  $ ftp ftp.openpkg.org
  ftp> bin
  ftp> cd release/1.2/UPD
  ftp> get openssh-3.5p1-1.2.2.src.rpm
  ftp> bye
  $ <prefix>/bin/rpm -v --checksig openssh-3.5p1-1.2.2.src.rpm
  $ <prefix>/bin/rpm --rebuild openssh-3.5p1-1.2.2.src.rpm
  $ su -
  # <prefix>/bin/rpm -Fvh <prefix>/RPM/PKG/openssh-3.5p1-1.2.2.*.rpm
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References:
  [0] http://lab.mediaservice.net/advisory/2003-01-openssh.txt
  [1] http://www.openssh.com/
  [2] http://cve.mitre.org/cgi-bin/cvename.cgi?name=CAN-2003-0190
  [3] http://www.openpkg.org/tutorial.html#regular-source
  [4] http://www.openpkg.org/tutorial.html#regular-binary
  [5] ftp://ftp.openpkg.org/release/1.2/UPD/openssh-3.5p1-1.2.2.src.rpm
  [6] ftp://ftp.openpkg.org/release/1.2/UPD/
  [7] http://www.openpkg.org/security.html#signature
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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 retrieve from http://pgp.openpkg.org and
hkp://pgp.openpkg.org. Follow the instructions on http://pgp.openpkg.org/
for details on how to verify the integrity of this advisory.
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