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-----BEGIN PGP SIGNED MESSAGE----- =========================================================================== AUSCERT External Security Bulletin Redistribution ESB-2001.365 -- FreeBSD-SA-01:57.sendmail sendmail contains local root vulnerability 28 August 2001 =========================================================================== AusCERT Security Bulletin Summary --------------------------------- Product: sendmail Operating System: FreeBSD BSD Unix Impact: Root Compromise Access Required: Local - --------------------------BEGIN INCLUDED TEXT-------------------- - -----BEGIN PGP SIGNED MESSAGE----- ============================================================================= FreeBSD-SA-01:57 Security Advisory FreeBSD, Inc. Topic: sendmail contains local root vulnerability Category: core Module: sendmail Announced: 2001-08-27 Credits: Cade Cairnss <cairnsc@securityfocus.com> Affects: FreeBSD 4-STABLE after August 27, 2000 and prior to the correction date, FreeBSD 4.1.1-RELEASE, 4.2-RELEASE, 4.3-RELEASE Corrected: 2001-08-21 01:36:37 UTC (FreeBSD 4.3-STABLE) 2001-08-22 05:34:11 UTC (RELENG_4_3) FreeBSD only: NO I. Background sendmail is a mail transfer agent. II. Problem Description Sendmail contains an input validation error which may lead to the execution of arbitrary code with elevated privileges by local users. Due to the improper use of signed integers in code responsible for the processing of debugging arguments, a local user may be able to supply the signed integer equivalent of a negative value supplied to sendmail's "trace vector". This may allow a local user to write data anywhere within a certain range of locations in process memory. Because the '-d' command-line switch is processed before the program drops its elevated privileges, the attacker may be able to cause arbitrary code to be executed with root privileges. III. Impact Local users may be able to execute arbitrary code with root privileges. IV. Workaround Do not allow untrusted users to execute the sendmail binary. V. Solution One of the following: 1) Upgrade your vulnerable FreeBSD system to 4.3-STABLE or the RELENG_4_3 security branch after the respective correction dates. 2) FreeBSD 4.x systems after August 27, 2000 and prior to the correction date: The following patch has been verified to apply to FreeBSD 4.1.1-RELEASE, 4.2-RELEASE, 4.3-RELEASE and 4-STABLE dated prior to the correction date. Download the patch and the detached PGP signature from the following locations, and verify the signature using your PGP utility. # fetch ftp://ftp.freebsd.org/pub/FreeBSD/CERT/patches/SA-01:57/sendmail.patch # fetch ftp://ftp.freebsd.org/pub/FreeBSD/CERT/patches/SA-01:57/sendmail.patch.asc Execute the following commands as root: # cd /usr/src # patch -p < /path/to/patch # cd /usr/src/lib/libsmutil # make depend && make all # cd /usr/src/usr.sbin/sendmail # make depend && make all install 3) FreeBSD 4.3-RELEASE systems: An experimental upgrade package is available for users who wish to provide testing and feedback on the binary upgrade process. This package may be installed on FreeBSD 4.3-RELEASE systems only, and is intended for use on systems for which source patching is not practical or convenient. If you use the upgrade package, feedback (positive or negative) to security-officer@FreeBSD.org is requested so we can improve the process for future advisories. During the installation procedure, backup copies are made of the files which are replaced by the package. These backup copies will be reinstalled if the package is removed, reverting the system to a pre-patched state. # fetch ftp://ftp.FreeBSD.org/pub/FreeBSD/CERT/packages/SA-01:57/security-patch-sendmail-01.57.tgz # fetch ftp://ftp.FreeBSD.org/pub/FreeBSD/CERT/packages/SA-01:57/security-patch-sendmail-01.57.tgz.asc Verify the detached PGP signature using your PGP utility. # pkg_add security-patch-sendmail-01:57.tgz Restart sendmail after applying the patch by executing the following commands as root: # killall sendmail # /usr/sbin/sendmail -bd -q30m The flags to sendmail may need to be adjusted as required for the local system configuration. VI. Correction details The following is the sendmail $Id$ revision number of the file that was corrected for the supported branches of FreeBSD. The $Id$ revision number of the installed source can be examined using the ident(1) command. Revision Path 8.20.22.4 src/contrib/sendmail/src/trace.c VII. References <URL:http://www.securityfocus.com/bid/3163> - -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.0.6 (FreeBSD) Comment: For info see http://www.gnupg.org iQCVAwUBO4q+6lUuHi5z0oilAQH2xQP/e5UR1/UiVoNLjWnZr/3Ufk11/Dx0jeux W43znQ3Hae7ZDK17bUvvJ0t3uSq7mgzP1EmHYhjWWvrVNOaKLNO2C7oiTBWeyNWj J+hk26jZQO74mQDdZVwIr4SbE+tMTUIfEcVcXv7++ZS3xbyh3wyQKZipD5UElnLs ek/7MzKM83E= =Lv0A - -----END PGP SIGNATURE----- - --------------------------END INCLUDED TEXT-------------------- You have received this e-mail bulletin as a result of your organisation's registration with AusCERT. The mailing list you are subscribed to is maintained within your organisation, so if you do not wish to continue receiving these bulletins you should contact your local IT manager. If you do not know who that is, please send an email to auscert@auscert.org.au and we will forward your request to the appropriate person. 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Previous advisories and external security bulletins can be retrieved from: http://www.auscert.org.au/Information/advisories.html If you believe that your system has been compromised, contact AusCERT or your representative in FIRST (Forum of Incident Response and Security Teams). Internet Email: auscert@auscert.org.au Facsimile: (07) 3365 7031 Telephone: (07) 3365 4417 (International: +61 7 3365 4417) AusCERT personnel answer during Queensland business hours which are GMT+10:00 (AEST). On call after hours for emergencies. -----BEGIN PGP SIGNATURE----- Version: 2.6.3i Charset: noconv Comment: ftp://ftp.auscert.org.au/pub/auscert/AUSCERT_PGP.key iQCVAwUBO4tv7ih9+71yA2DNAQESYQP/fjLTORN5HZ3xl9aENPH8l2E4p9fYCUxP zt4DqoRQf0G4603DVLJb7jqp7DfqPfPWCZFGg92AM64GJzsSi2BfWbfOmZTltMyz 8V0acFoFkC0ukx/o0tA5LmzcSFsiv9ctIsy3eiT8D/y8HMIoTIcOyTmX/mtZrMkh 1zWHWrFUru4= =a65/ -----END PGP SIGNATURE-----