============================================================================= FreeBSD-SA-03:07 Security Advisory The FreeBSD Project Topic: a second sendmail header parsing buffer overflow Category: contrib Module: src/contrib/sendmail Announced: 2003-03-30 Credits: Michal Zalewski Affected: 4.8-RELEASE, 5.0-RELEASE-p7, and FreeBSD 4-STABLE Corrected: RELENG_3 on 2003-03-29 20:09:48 UTC, RELENG_4 on 2003-03-29 19:34:13 UTC, RELENG_4_3 on 2003-03-29 21:57:36 UTC, RELENG_4_4 on 2003-03-29 21:57:45 UTC, RELENG_4_5 on 2003-03-29 21:57:52 UTC, RELENG_4_6 on 2003-03-29 21:57:58 UTC, RELENG_4_7 on 2003-03-29 21:58:05 UTC, RELENG_4_7 on 2003-03-29 21:58:05 UTC, and RELENG_5_0 on 2003-03-29 21:58:11 UTC Vendor status: corrected 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 =============================================================================