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FreeBSD-SA-06:17.sendmail                                   Security Advisory
                                                          The FreeBSD Project

Topic:          Incorrect multipart message handling in Sendmail

Category:       contrib
Module:         contrib_sendmail
Announced:      2006-06-14
Affects:        All FreeBSD releases.
Corrected:      2006-06-14 15:58:23 UTC (RELENG_6, 6.1-STABLE)
                2006-06-14 15:59:28 UTC (RELENG_6_1, 6.1-RELEASE-p2)
                2006-06-14 15:59:37 UTC (RELENG_6_0, 6.0-RELEASE-p9)
                2006-06-14 16:00:02 UTC (RELENG_5, 5.5-STABLE)
                2006-06-14 16:00:22 UTC (RELENG_5_5, 5.5-RELEASE-p2)
                2006-06-14 16:00:42 UTC (RELENG_5_4, 5.4-RELEASE-p16)
                2006-06-14 16:00:56 UTC (RELENG_5_3, 5.3-RELEASE-p31)
                2006-06-14 16:01:06 UTC (RELENG_4, 4.11-STABLE)
                2006-06-14 16:01:21 UTC (RELENG_4_11, 4.11-RELEASE-p19)
CVE Name:       CVE-2006-1173

For general information regarding FreeBSD Security Advisories,
including descriptions of the fields above, security branches, and the
following sections, please visit
<URL:http://security.freebsd.org/>.

I.   Background

FreeBSD includes sendmail(8), a general purpose internetwork mail
routing facility, as the default Mail Transfer Agent (MTA).

II.  Problem Description

A suitably malformed multipart MIME message can cause sendmail to exceed
predefined limits on its stack usage.

III. Impact

An attacker able to send mail to, or via, a server can cause queued
messages on the system to not be delivered, by causing the sendmail process
which handles queued messages to crash.  Note that this will not stop new
messages from entering the queue (either from local processes, or incoming
via SMTP).

IV.  Workaround

No workaround is available, but systems which do not receive email from
untrusted sources are not vulnerable.

V.   Solution

Perform one of the following:

1) Upgrade your vulnerable system to 4-STABLE, 5-STABLE, or 6-STABLE,
or to the RELENG_6_1, RELENG_6_0, RELENG_5_5, RELENG_5_4, RELENG_5_3,
or RELENG_4_11 security branch dated after the correction date.

2) To patch your present system:

The following patches have been verified to apply to FreeBSD 4.11, 5.3,
5.4, 5.5, 6.0, and 6.1 systems.

a) Download the relevant patch from the location below, and verify the
detached PGP signature using your PGP utility.

# fetch http://security.FreeBSD.org/patches/SA-06:17/sendmail.patch
# fetch http://security.FreeBSD.org/patches/SA-06:17/sendmail.patch.asc

b) Execute the following commands as root:

# cd /usr/src
# patch < /path/to/patch
# cd /usr/src/lib/libsm
# make obj && make depend && make
# cd /usr/src/lib/libsmutil
# make obj && make depend && make
# cd /usr/src/usr.sbin/sendmail
# make obj && make depend && make && make install

VI.  Correction details

The following list contains the revision numbers of each file that was
corrected in FreeBSD.

Branch                                                           Revision
  Path
- -------------------------------------------------------------------------
RELENG_4
  src/contrib/sendmail/src/deliver.c                         1.1.1.3.2.24
  src/contrib/sendmail/src/mime.c                            1.1.1.3.2.14
  src/contrib/sendmail/src/sendmail.h                        1.1.1.4.2.31
RELENG_4_11
  src/UPDATING                                             1.73.2.91.2.19
  src/sys/conf/newvers.sh                                  1.44.2.39.2.22
  src/contrib/sendmail/src/deliver.c                     1.1.1.3.2.17.2.2
  src/contrib/sendmail/src/mime.c                         1.1.1.3.2.8.2.2
  src/contrib/sendmail/src/sendmail.h                    1.1.1.4.2.19.2.2
RELENG_5
  src/contrib/sendmail/src/deliver.c                         1.1.1.21.2.6
  src/contrib/sendmail/src/mime.c                            1.1.1.12.2.5
  src/contrib/sendmail/src/sendmail.h                        1.1.1.23.2.6
RELENG_5_5
  src/UPDATING                                             1.342.2.35.2.1
  src/sys/conf/newvers.sh                                   1.62.2.21.2.3
  src/contrib/sendmail/src/deliver.c                     1.1.1.21.2.4.2.1
  src/contrib/sendmail/src/mime.c                        1.1.1.12.2.3.2.1
  src/contrib/sendmail/src/sendmail.h                    1.1.1.23.2.4.2.1
RELENG_5_4
  src/UPDATING                                            1.342.2.24.2.24
  src/sys/conf/newvers.sh                                  1.62.2.18.2.20
  src/contrib/sendmail/src/deliver.c                     1.1.1.21.2.1.2.2
  src/contrib/sendmail/src/mime.c                        1.1.1.12.2.1.2.2
  src/contrib/sendmail/src/sendmail.h                    1.1.1.23.2.1.2.2
RELENG_5_3
  src/UPDATING                                            1.342.2.13.2.33
  src/sys/conf/newvers.sh                                  1.62.2.15.2.35
  src/contrib/sendmail/src/deliver.c                         1.1.1.21.4.2
  src/contrib/sendmail/src/mime.c                            1.1.1.12.4.2
  src/contrib/sendmail/src/sendmail.h                        1.1.1.23.4.2
RELENG_6
  src/contrib/sendmail/src/deliver.c                         1.1.1.23.2.3
  src/contrib/sendmail/src/mime.c                            1.1.1.13.2.3
  src/contrib/sendmail/src/sendmail.h                        1.1.1.26.2.3
RELENG_6_1
  src/UPDATING                                             1.416.2.22.2.3
  src/sys/conf/newvers.sh                                   1.69.2.11.2.3
  src/contrib/sendmail/src/deliver.c                     1.1.1.23.2.2.2.1
  src/contrib/sendmail/src/mime.c                        1.1.1.13.2.2.2.1
  src/contrib/sendmail/src/sendmail.h                    1.1.1.26.2.2.2.1
RELENG_6_0
  src/UPDATING                                             1.416.2.3.2.13
  src/sys/conf/newvers.sh                                    1.69.2.8.2.9
  src/contrib/sendmail/src/deliver.c                         1.1.1.23.4.2
  src/contrib/sendmail/src/mime.c                            1.1.1.13.4.2
  src/contrib/sendmail/src/sendmail.h                        1.1.1.26.4.2
- -------------------------------------------------------------------------

VII. References

http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2006-1173

The latest revision of this advisory is available at
http://security.FreeBSD.org/advisories/FreeBSD-SA-06:17.sendmail.asc
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