[FUGSPBR] FWD: A second sendmail header parsing buffer overflow

Paulo R Herculano HerculPR em appliedbiosystems.com
Seg Mar 31 10:38:07 BRT 2003


Para quem usa sendmail!!

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=============================================================================
FreeBSD-SA-03:07.sendmail                                   Security
Advisory
                                                          The FreeBSD
Project

Topic:          a second sendmail header parsing buffer overflow

Category:       contrib
Module:         contrib_sendmail
Announced:      2003-03-30
Credits:        Michal Zalewski <lcamtuf em ghettot.org>
Affects:        All releases prior to 4.8-RELEASE and 5.0-RELEASE-p7
                FreeBSD 4-STABLE prior to the correction date
Corrected:      2003-03-29 19:34:13 UTC (RELENG_4)
                2003-03-29 21:58:11 UTC (RELENG_5_0)
                2003-03-29 21:58:05 UTC (RELENG_4_7)
                2003-03-29 21:57:58 UTC (RELENG_4_6)
                2003-03-29 21:57:52 UTC (RELENG_4_5)
                2003-03-29 21:57:45 UTC (RELENG_4_4)
                2003-03-29 21:57:36 UTC (RELENG_4_3)
                2003-03-29 20:09:48 UTC (RELENG_3)
FreeBSD only:   NO

I.   Background

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

II.  Problem Description

A buffer overflow that may occur during header parsing was identified.
The overflow is possible due to a programming error involving type
conversions in the C programming language.

NOTE WELL:  This issue is distinct from the issue described in
`FreeBSD-SA-03:04.sendmail', although the impact is very similar.

III. Impact

A remote attacker could create a specially crafted message that may
cause sendmail to execute arbitrary code with the privileges of the
user running sendmail, typically root.  The malicious message might be
handled (and the vulnerability triggered) by the initial
sendmail MTA, by any relaying sendmail MTA, or by the delivering sendmail
process.  Exploiting this defect is particularly difficult, but is
believed to be possible.

The defect in the ident routines is not believed to be exploitable.

IV.  Workaround

There is no workaround, other than not using sendmail.

V.   Solution

Do one of the following:

1) Upgrade your vulnerable system to 4-STABLE or 4.8-RELEASE; or
to the RELENG_5_0, RELENG_4_7, or RELENG_4_6 security branch dated
after the correction date (5.0-RELEASE-p7, 4.7-RELEASE-p10, or
4.6.2-RELEASE-p13, respectively).

2) To patch your present system:

The following patch has been verified to apply to FreeBSD 5.0, 4.7,
and 4.6 systems.

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

ftp://ftp.FreeBSD.org/pub/FreeBSD/CERT/patches/SA-03:07/sendmail.patch
ftp://ftp.FreeBSD.org/pub/FreeBSD/CERT/patches/SA-03:07/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

c) Restart sendmail.  Execute the following command as root.

# /bin/sh /etc/rc.sendmail restart

3) For i386 systems only, a patched sendmail binary is available.
Select the correct binary based on your FreeBSD version and whether or
not you want STARTTLS support.  If you want STARTTLS support, you must
have the crypto distribution installed.

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

ftp://ftp.FreeBSD.org/pub/FreeBSD/CERT/patches/SA-03:07/sendmail-4.6-i386-crypto.bin.gz
ftp://ftp.FreeBSD.org/pub/FreeBSD/CERT/patches/SA-03:07/sendmail-4.6-i386-crypto.bin.gz.asc

ftp://ftp.FreeBSD.org/pub/FreeBSD/CERT/patches/SA-03:07/sendmail-4.6-i386-nocrypto.bin.gz
ftp://ftp.FreeBSD.org/pub/FreeBSD/CERT/patches/SA-03:07/sendmail-4.6-i386-nocrypto.bin.gz.asc

ftp://ftp.FreeBSD.org/pub/FreeBSD/CERT/patches/SA-03:07/sendmail-4.7-i386-crypto.bin.gz
ftp://ftp.FreeBSD.org/pub/FreeBSD/CERT/patches/SA-03:07/sendmail-4.7-i386-crypto.bin.gz.asc

ftp://ftp.FreeBSD.org/pub/FreeBSD/CERT/patches/SA-03:07/sendmail-4.7-i386-nocrypto.bin.gz
ftp://ftp.FreeBSD.org/pub/FreeBSD/CERT/patches/SA-03:07/sendmail-4.7-i386-nocrypto.bin.gz.asc

ftp://ftp.FreeBSD.org/pub/FreeBSD/CERT/patches/SA-03:07/sendmail-5.0-i386-crypto.bin.gz
ftp://ftp.FreeBSD.org/pub/FreeBSD/CERT/patches/SA-03:07/sendmail-5.0-i386-crypto.bin.gz.asc

ftp://ftp.FreeBSD.org/pub/FreeBSD/CERT/patches/SA-03:07/sendmail-5.0-i386-nocrypto.bin.gz
ftp://ftp.FreeBSD.org/pub/FreeBSD/CERT/patches/SA-03:07/sendmail-5.0-i386-nocrypto.bin.gz.asc

b) Install the binary.  Execute the following commands as root.
Note that these examples utilizes the FreeBSD 4.7 crypto binary.
Substitute BINARYGZ with the name of the file which you downloaded in
step (a).

# BINARYGZ=/path/to/sendmail-4.7-i386-crypto.bin.gz
# gunzip ${BINARYGZ}
# install -s -o root -g smmsp -m 2555 ${BINARYGZ%.gz}
/usr/libexec/sendmail/sendmail

c) Restart sendmail.  Execute the following command as root.

# /bin/sh /etc/rc.sendmail restart

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/FREEBSD-upgrade                           1.1.2.16
  src/contrib/sendmail/RELEASE_NOTES                         1.1.1.3.2.15
  src/contrib/sendmail/cf/README                             1.1.1.3.2.15
  src/contrib/sendmail/cf/cf/submit.cf                        1.1.1.1.2.8
  src/contrib/sendmail/cf/m4/cfhead.m4                            1.3.6.8
  src/contrib/sendmail/cf/m4/proto.m4                        1.1.1.4.2.13
  src/contrib/sendmail/cf/m4/version.m4                      1.1.1.3.2.15
  src/contrib/sendmail/cf/mailer/usenet.m4                    1.1.1.2.6.3
  src/contrib/sendmail/contrib/buildvirtuser                  1.1.1.1.2.5
  src/contrib/sendmail/doc/op/op.me                          1.1.1.3.2.15
  src/contrib/sendmail/editmap/editmap.8                      1.1.1.1.2.2
  src/contrib/sendmail/include/sm/bdb.h                       1.1.1.1.2.2
  src/contrib/sendmail/include/sm/conf.h                      1.1.1.1.2.7
  src/contrib/sendmail/libmilter/docs/api.html                1.1.1.1.2.2
  src/contrib/sendmail/libmilter/docs/design.html             1.1.1.1.2.2
  src/contrib/sendmail/libmilter/docs/index.html              1.1.1.1.2.2
  src/contrib/sendmail/libmilter/docs/installation.html       1.1.1.1.2.3
  src/contrib/sendmail/libmilter/docs/other.html              1.1.1.1.2.2
  src/contrib/sendmail/libmilter/docs/overview.html           1.1.1.1.2.2
  src/contrib/sendmail/libmilter/docs/sample.html             1.1.1.1.2.3
  src/contrib/sendmail/libmilter/docs/smfi_addheader.html     1.1.1.1.2.3
  src/contrib/sendmail/libmilter/docs/smfi_addrcpt.html       1.1.1.1.2.2
  src/contrib/sendmail/libmilter/docs/smfi_chgheader.html     1.1.1.1.2.3
  src/contrib/sendmail/libmilter/docs/smfi_delrcpt.html       1.1.1.1.2.2
  src/contrib/sendmail/libmilter/docs/smfi_getpriv.html       1.1.1.1.2.2
  src/contrib/sendmail/libmilter/docs/smfi_getsymval.html     1.1.1.1.2.3
  src/contrib/sendmail/libmilter/docs/smfi_main.html          1.1.1.1.2.2
  src/contrib/sendmail/libmilter/docs/smfi_register.html      1.1.1.1.2.2
  src/contrib/sendmail/libmilter/docs/smfi_replacebody.html   1.1.1.1.2.2
  src/contrib/sendmail/libmilter/docs/smfi_setbacklog.html    1.1.1.1.2.2
  src/contrib/sendmail/libmilter/docs/smfi_setconn.html       1.1.1.1.2.2
  src/contrib/sendmail/libmilter/docs/smfi_setpriv.html       1.1.1.1.2.2
  src/contrib/sendmail/libmilter/docs/smfi_setreply.html      1.1.1.1.2.4
  src/contrib/sendmail/libmilter/docs/smfi_settimeout.html    1.1.1.1.2.3
  src/contrib/sendmail/libmilter/docs/xxfi_abort.html         1.1.1.1.2.2
  src/contrib/sendmail/libmilter/docs/xxfi_body.html          1.1.1.1.2.2
  src/contrib/sendmail/libmilter/docs/xxfi_close.html         1.1.1.1.2.2
  src/contrib/sendmail/libmilter/docs/xxfi_connect.html       1.1.1.1.2.2
  src/contrib/sendmail/libmilter/docs/xxfi_envfrom.html       1.1.1.1.2.2
  src/contrib/sendmail/libmilter/docs/xxfi_envrcpt.html       1.1.1.1.2.2
  src/contrib/sendmail/libmilter/docs/xxfi_eoh.html           1.1.1.1.2.2
  src/contrib/sendmail/libmilter/docs/xxfi_eom.html           1.1.1.1.2.2
  src/contrib/sendmail/libmilter/docs/xxfi_header.html        1.1.1.1.2.2
  src/contrib/sendmail/libmilter/docs/xxfi_helo.html          1.1.1.1.2.2
  src/contrib/sendmail/libsm/clock.c                          1.1.1.1.2.5
  src/contrib/sendmail/libsm/config.c                         1.1.1.1.2.3
  src/contrib/sendmail/mail.local/mail.local.c                   1.6.6.14
  src/contrib/sendmail/src/README                            1.1.1.3.2.14
  src/contrib/sendmail/src/collect.c                         1.1.1.4.2.12
  src/contrib/sendmail/src/conf.c                                1.5.2.14
  src/contrib/sendmail/src/deliver.c                         1.1.1.3.2.14
  src/contrib/sendmail/src/headers.c                             1.4.2.10
  src/contrib/sendmail/src/main.c                            1.1.1.3.2.15
  src/contrib/sendmail/src/milter.c                          1.1.1.1.2.16
  src/contrib/sendmail/src/parseaddr.c                       1.1.1.2.6.13
  src/contrib/sendmail/src/queue.c                           1.1.1.3.2.14
  src/contrib/sendmail/src/readcf.c                          1.1.1.4.2.14
  src/contrib/sendmail/src/sendmail.h                        1.1.1.4.2.15
  src/contrib/sendmail/src/sm_resolve.c                       1.1.1.1.2.3
  src/contrib/sendmail/src/srvrsmtp.c                        1.1.1.2.6.14
  src/contrib/sendmail/src/tls.c                              1.1.1.1.2.5
  src/contrib/sendmail/src/usersmtp.c                        1.1.1.3.2.12
  src/contrib/sendmail/src/version.c                         1.1.1.3.2.15
RELENG_5_0
  src/UPDATING                                                 1.229.2.13
  src/contrib/sendmail/src/conf.c                                1.18.2.1
  src/contrib/sendmail/src/parseaddr.c                       1.1.1.14.2.2
  src/contrib/sendmail/src/version.c                         1.1.1.16.2.1
  src/sys/conf/newvers.sh                                        1.48.2.8
RELENG_4_7
  src/UPDATING                                             1.73.2.74.2.13
  src/contrib/sendmail/src/conf.c                            1.5.2.11.2.1
  src/contrib/sendmail/src/parseaddr.c                   1.1.1.2.6.10.2.2
  src/contrib/sendmail/src/version.c                     1.1.1.3.2.12.2.1
  src/sys/conf/newvers.sh                                  1.44.2.26.2.12
RELENG_4_6
  src/UPDATING                                             1.73.2.68.2.41
  src/contrib/sendmail/src/conf.c                             1.5.2.8.2.1
  src/contrib/sendmail/src/parseaddr.c                    1.1.1.2.6.8.2.2
  src/contrib/sendmail/src/version.c                      1.1.1.3.2.9.2.1
  src/sys/conf/newvers.sh                                  1.44.2.23.2.30
RELENG_4_5
  src/UPDATING                                             1.73.2.50.2.43
  src/contrib/sendmail/src/conf.c                             1.5.2.6.4.1
  src/contrib/sendmail/src/parseaddr.c                    1.1.1.2.6.6.4.2
  src/contrib/sendmail/src/version.c                      1.1.1.3.2.7.4.1
  src/sys/conf/newvers.sh                                  1.44.2.20.2.27
RELENG_4_4
  src/UPDATING                                             1.73.2.43.2.43
  src/contrib/sendmail/src/conf.c                             1.5.2.6.2.1
  src/contrib/sendmail/src/parseaddr.c                    1.1.1.2.6.6.2.2
  src/contrib/sendmail/src/version.c                      1.1.1.3.2.7.2.1
  src/sys/conf/newvers.sh                                  1.44.2.17.2.34
RELENG_4_3
  src/UPDATING                                             1.73.2.28.2.31
  src/contrib/sendmail/src/conf.c                             1.5.2.4.2.1
  src/contrib/sendmail/src/parseaddr.c                    1.1.1.2.6.4.2.2
  src/contrib/sendmail/src/version.c                      1.1.1.3.2.4.2.1
  src/sys/conf/newvers.sh                                  1.44.2.14.2.21
RELENG_3
  src/contrib/sendmail/src/conf.c                                 1.3.2.3
  src/contrib/sendmail/src/parseaddr.c                        1.1.1.2.2.2
  src/contrib/sendmail/src/version.c                          1.1.1.2.2.2
- -------------------------------------------------------------------------

VII. References

<URL: http://www.cert.org/advisories/CA-2003-12.html >
<URL: http://www.sendmail.com/security/ >
<URL:
http://lists.netsys.com/pipermail/full-disclosure/2003-March/008973.html >
<URL: http://cve.mitre.org/cgi-bin/cvename.cgi?name=CAN-2003-0161 >
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Att, Paulo R. Herculano
IT Trainee
Applied Biosystems

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