[SECURITY] Fedora 23 Update: opensmtpd-5.7.3p1-1.fc23

[updates at fedoraproject.org]

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Fedora Update Notification
FEDORA-2015-ed1c673f09
2015-11-01 01:51:21.182042
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Name        : opensmtpd
Product     : Fedora 23
Version     : 5.7.3p1
Release     : 1.fc23
URL         : http://www.opensmtpd.org/
Summary     : Free implementation of the server-side SMTP protocol as defined by RFC 5321
Description :
OpenSMTPD is a FREE implementation of the server-side SMTP protocol as defined
by RFC 5321, with some additional standard extensions. It allows ordinary
machines to exchange e-mails with other systems speaking the SMTP protocol.
Started out of dissatisfaction with other implementations, OpenSMTPD nowadays
is a fairly complete SMTP implementation. OpenSMTPD is primarily developed
by Gilles Chehade, Eric Faurot and Charles Longeau; with contributions from
various OpenBSD hackers. OpenSMTPD is part of the OpenBSD Project.
The software is freely usable and re-usable by everyone under an ISC license.

This package uses standard "alternatives" mechanism, you may call
"/usr/sbin/alternatives --set mta /usr/sbin/sendmail.opensmtpd"
if you want to switch to OpenSMTPD MTA immediately after install, and
"/usr/sbin/alternatives --set mta /usr/sbin/sendmail.sendmail" to revert
back to Sendmail as a default mail daemon.

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Update Information:

Issues fixed in this release (since 5.7.2):  - fix an mda buffer truncation bug
which allows a user to create forward   files that pass session checks but fail
delivery later down the chain,   within the user mda; - fix remote buffer
overflow in unprivileged pony process; - reworked offline enqueue to better
protect against hardlink attacks.  ----  Several vulnerabilities have been fixed
in OpenSMTPD 5.7.2:  - an oversight in the portable version of fgetln() that
allows attackers to read and write out-of-bounds memory;  - multiple denial-of-
service vulnerabilities that allow local users to kill or hang OpenSMTPD;  - a
stack-based buffer overflow that allows local users to crash OpenSMTPD, or
execute arbitrary code as the non-chrooted _smtpd user;  - a hardlink attack (or
race-conditioned symlink attack) that allows local users to unset the chflags()
of arbitrary files;  - a hardlink attack that allows local users to read the
first line of arbitrary files (for example, root's hash from
/etc/master.passwd);  - a denial-of-service vulnerability that allows remote
attackers to fill OpenSMTPD's queue or mailbox hard-disk partition;  - an out-
of-bounds memory read that allows remote attackers to crash OpenSMTPD, or leak
information and defeat the ASLR protection;  - a use-after-free vulnerability
that allows remote attackers to crash OpenSMTPD, or execute arbitrary code as
the non-chrooted _smtpd user;  Further details can be found in Qualys' audit
report: http://seclists.org/oss-sec/2015/q4/17  MITRE has assigned one CVE for
the use-after-free vulnerability; additional CVEs may be assigned:
http://seclists.org/oss-sec/2015/q4/23  External References:
https://www.opensmtpd.org/announces/release-5.7.2.txt http://seclists.org/oss-
sec/2015/q4/17
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References:

  [ 1 ] Bug #1268837 - opensmtpd-5.7.3 is available
        https://bugzilla.redhat.com/show_bug.cgi?id=1268837
  [ 2 ] Bug #1268509 - opensmtpd: 5.7.2 release available
        https://bugzilla.redhat.com/show_bug.cgi?id=1268509
  [ 3 ] Bug #1268794 - CVE-2015-7687 OpenSMTPD: multiple vulnerabilities fixed in 5.7.2 [fedora-all]
        https://bugzilla.redhat.com/show_bug.cgi?id=1268794
  [ 4 ] Bug #1268857 - opensmtpd: Remotely triggerable buffer overflow vulnerability in filter_tx_io [fedora-all]
        https://bugzilla.redhat.com/show_bug.cgi?id=1268857
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This update can be installed with the "yum" update program. Use
su -c 'yum update opensmtpd' at the command line.
For more information, refer to "Managing Software with yum",
available at https://docs.fedoraproject.org/yum/.

All packages are signed with the Fedora Project GPG key.  More details on the
GPG keys used by the Fedora Project can be found at
https://fedoraproject.org/keys
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