-----BEGIN PGP SIGNED MESSAGE----- ______________________________________________________________________________ SuSE Security Announcement Package: sendmail Announcement-ID: SuSE-SA:2001:028 Date: Thursday, Aug 23rd 2001 18:10 MEST Affected SuSE versions: 7.0, 7.1, 7.2 Vulnerability Type: local root compromise Severity (1-10): 5 SuSE default package: yes Other affected systems: systems using the sendmail package Content of this advisory: 1) security vulnerability resolved: sendmail problem description, discussion, solution and upgrade information 2) pending vulnerabilities, solutions, workarounds 3) standard appendix (further information) ______________________________________________________________________________ 1) problem description, brief discussion, solution, upgrade information Cade Cairns of Securityfocus discovered a vulnerability in the sendmail program, the widely spread MTA used in Unix- and Unix-like systems. A local user can write arbitrary data to the process memory, resulting in user-controlled code to be executed as user root. Please note that this is a _local_ vulnerability: Local shell access is needed for the attacker to be able to take advantage of this error. The /usr/sbin/sendmail program is installed set-uid root in most installations. This special privilege is needed for the sendmail program to operate properly. The attack pattern involves running sendmail to make use of the setuid-bit. Please note that this is the first sendmail security problem since 1997. In this case, the vulnerability can be classified as a commandline processing bug while running with extended (root) privilege. The error itself is a result of a comparison between a signed and an unsigned integer when checking user-supplied data from the sendmail command line: A high unsigned value is being considered a negative signed value. A subsequent comparison is being evaluated the wrong way. These errors are expected to make up a new class of vulnerabilities for programs written in C in the near future. The supported SuSE Linux distributions 6.3 and 6.4 use a sendmail of version 8.9.3. According to Sendmail Inc., this version is not affected by this signedness bug. The SuSE Linux distributions 7.0, 7.1 and 7.2 use sendmail version 8.11.x. All 7.x distributions are affected by the problem. SuSE provides update packages for the affected distributions. Please download the update package for your distribution and use the command 'rpm -Uhv file.rpm' to apply the update. It is recommended to stop the running sendmail process(es) before applying the update. Use the command 'rcsendmail stop' to do this, and 'rcsendmail start' to restart the service after the update has been applied. Since the update packages only fix the security problem from this announcement, no reconfiguration should be necessary. SPECIAL INSTALL INSTRUCTIONS: The sendmail package needs one out of two commands to be executed after package installation. Use the commands SuSEconfig or, alternatively (if you have disabled SuSEconfig in /etc/rc.config), chkstat -set /etc/permissions.d/sendmail to set the permissions of the sendmail package files correctly. Without these permission changes, the /usr/sbin/sendmail program will not operate properly. (Side note: All of the commands above have to be run as root!) i386 Intel Platform: SuSE-7.2 ftp://ftp.suse.com/pub/suse/i386/update/7.2/n1/sendmail-8.11.3-68.i386.rpm edffc3231b74858c218e540ffb37740a SuSE-7.2 ftp://ftp.suse.com/pub/suse/i386/update/7.2/sec2/sendmail-tls-8.11.3-72.i386.rpm 6a99faaaf394ab7b6dd22d9d81fb221b source rpm: ftp://ftp.suse.com/pub/suse/i386/update/7.2/zq1/sendmail-8.11.3-68.src.rpm e914fef1f5fb1c65bb7b52383f9832db SuSE-7.1 ftp://ftp.suse.com/pub/suse/i386/update/7.1/n1/sendmail-8.11.2-34.i386.rpm 6cf817fe71a07fc58d4b201df01291b5 SuSE-7.1 ftp://ftp.suse.com/pub/suse/i386/update/7.1/sec2/sendmail-tls-8.11.2-29.i386.rpm d96f3e373f7c628d5792a2567e02e4c3 source rpm: ftp://ftp.suse.com/pub/suse/i386/update/7.1/zq1/sendmail-8.11.2-34.src.rpm 35c53244eafc645d4d9218d95c4f6d71 SuSE-7.0 ftp://ftp.suse.com/pub/suse/i386/update/7.0/n1/sendmail-8.11.0-5.i386.rpm 29250e9986dfd22c7bdf637ac5dcc646 source rpm: ftp://ftp.suse.com/pub/suse/i386/update/7.0/zq1/sendmail-8.11.0-5.src.rpm 13153a10c4223450119d2bd57178b8d4 Sparc Platform: SuSE-7.1 ftp://ftp.suse.com/pub/suse/sparc/update/7.1/n1/sendmail-8.11.2-17.sparc.rpm 08b83155a16e86bf0b41596b66115443 SuSE-7.1 ftp://ftp.suse.com/pub/suse/sparc/update/7.1/sec2/sendmail-tls-8.11.2-16.sparc.rpm 3d0b567682df307f13e552b4f85b798b source rpm: ftp://ftp.suse.com/pub/suse/sparc/update/7.1/zq1/sendmail-8.11.2-17.src.rpm a67beda92d8cbae62e8d69b263970108 SuSE-7.0 ftp://ftp.suse.com/pub/suse/sparc/update/7.0/n1/sendmail-8.11.0-3.sparc.rpm 17c9c5ce0814ee9821d7646d7ea399de source rpm: ftp://ftp.suse.com/pub/suse/sparc/update/7.0/zq1/sendmail-8.11.0-3.src.rpm d737219fb680f990d52faff49d53a48f AXP Alpha Platform: SuSE-7.1 ftp://ftp.suse.com/pub/suse/axp/update/7.1/n1/sendmail-8.11.2-19.alpha.rpm 6b7729f0c2b5dde8abb55102310bc039 SuSE-7.1 ftp://ftp.suse.com/pub/suse/axp/update/7.1/sec2/sendmail-tls-8.11.2-21.alpha.rpm c49dd3298689e2247a5228dfb3022949 source rpm: ftp://ftp.suse.com/pub/suse/axp/update/7.1/zq1/sendmail-8.11.2-19.src.rpm bfa6c0c95baa236cebcf501e4efdb0e9 PPC Power PC Platform: SuSE-7.1 ftp://ftp.suse.com/pub/suse/ppc/update/7.1/n1/sendmail-8.11.2-23.ppc.rpm 1ad2a5891a03cffd33baab76d0aed4f9 SuSE-7.1 ftp://ftp.suse.com/pub/suse/ppc/update/7.1/sec2/sendmail-tls-8.11.2-21.ppc.rpm b1181efdc649f005bc4a2b3fce08d164 source rpm: ftp://ftp.suse.com/pub/suse/ppc/update/7.1/zq1/sendmail-8.11.2-23.src.rpm 4caafc40ff5332dab46cc60e3f2a85fb SuSE-7.0 ftp://ftp.suse.com/pub/suse/ppc/update/7.0/n1/sendmail-8.11.0-33.ppc.rpm 27d5ac4d6d809a1ae88cf6a3fefe1d64 source rpm: ftp://ftp.suse.com/pub/suse/ppc/update/7.0/zq1/sendmail-8.11.0-33.src.rpm f6600b2aac4d3f8356494a3d047c72f9 ______________________________________________________________________________ 2) Pending vulnerabilities in SuSE Distributions, Workarounds and misc: - ftp server Our ftp server ftp.suse.com has been reorganized. The changes in particular are: * The discontinued distributions (SuSE Linux before (and including) 6.2) have moved to an own tree: /pub/suse/discontinued/<arch>. The tree there is built exactly like the tree for the currently supported distributions (6.3 and up). This change has been made to keep users from automatically applying updates against old problems that have been superceded by newer updates which are not available for the discontinued distributions. * The /pub/suse/<arch>/{KDE,KDE2,GNOME,X} directories have been moved to an own tree: /pub/suse/<arch>/supplementary/. The KDE directory has become famous in the KDE scene because it contains the latest KDE packages compiled for a SuSE distribution. This has been done to point out that the packages in this directory have been built for the respective distribution, they are tested ok, but since these packages have never been part of the distribution they are built for, there is no support for them; the packages are provided as-is. * During the next days, all packages under the /pub/suse/<arch>/update/ tree will be gpg-signed with the build@suse.de DSA key (see section 3 of this announcement). Currently, most of the formerly existing directories that have been moved are now still visible through a symlink, pointing at a directory with a README. The directory paths to the update packages for the supported distributions have _not_ changed. We kindly request mirror admins to adopt the changes to their trees. If you run a publically accessible mirror of ftp.suse.com, you are invited to send a mail to ftpadmin@suse.com so that you are being notified of such changes in advance. - in.telnetd A buffer overflow vulnerability has been found in the in.telnetd telned daemon, a service that is enabled by default in all SuSE Linux distributions. The vulnerability may allow a remote attacker to gain root access to your system. Many unix- and unix-like operating systems are affected by this or a similar problem. There are update packages for the SuSE Linux distributions 7.1 and 7.2 on our ftp server. The packages for the 7.1 distribution are called "nkitserv", for the 7.2 distributions, the name is telnet-server. For completeness, we also provide the other packages that are made from the same source rpm. Since these packages do not fix a security problem, there is no reason to list them here. We are working on a suitable solution for the 7.0 and 6.x distributions, while it has turned out that a fix for these distributions is non-trivial because a different code base has been used for these packages. telnet is an unencrypted protocol that offers many attack possibilities. If at all possible, please deactivate your telnetd by commenting it out in /etc/inetd.conf (killall -HUP inetd afterwards to make inetd reload its configuration file!). We recommend to use one of the two ssh implementations on our distributions as a substitute of the telnet protocol. Clients are available on the internet for most platforms and operating systems. An announcement will be released soon that addresses the problem in in.telnetd. - Yesterday (Wednesday, 20010822) Bob Vickers (Dept of Computer Science, University of London) reported a locally exploitable security hole in the script /etc/init.d/boot. The critical function of the script is supposed to remove files from the defined temporary directories of the system as specified in /etc/rc.config (TMP_DIRS_TO_CLEAR in /etc/rc.config) if $CLEAR_TMP_DIRS_AT_BOOTUP (also from /etc/rc.config) is set to "yes". Unfortunately, the script does not take into account that directories can contain newlines and other non-standard characters. By consequence, the script can be tricked to removing files elsewhere. This bug is present in the SuSE Linux 7.2 version only, available for the Intel i386 platform. The feature responsible for this bug is disabled by default in a SuSE Linux 7.2 installation and must be manually activated for the bug to impose any risk. We have fixed the problem in an update package that is available at ftp://ftp.suse.com/pub/suse/i386/update/7.2/a1/aaa_base-2001.8.23-0.i386.rpm Please download and install the update package using the command rpm -Uhv aaa_base-2001.8.23-0.i386.rpm Disregard the messages on standard output if you have the gpg package installed: The postinstall script adds the DSA key build@suse.de to root's gpg public keyring if this hasn't been done already. This key is also listed below. A source rpm is also available at the usual location. We will not issue a dedicated security announcement for this problem. We thank Bob Vickers for reporting the problem to security@suse.de. - openssl A weakness was found in the PRNG (Pseudo Random Number Generator) of the openssl package. As far as we could determine, the bug has no effect on the packages that are compiled against a library from the openssl package. We will however provide update packages that fix the found problems. Since openssl packages are not (backwards-) compatible to any other newer version, we have to fix the package for each distribution seperately. This takes some time. A special announce- ment will be issued as soon as all packages are available. - more announcements are in our queue. Please keep watching activity on the suse-security-announce@suse.com mailinglist (more information below). ______________________________________________________________________________ 3) standard appendix: authenticity verification, additional information - Package authenticity verification: SuSE update packages are available on many mirror ftp servers all over the world. While this service is being considered valuable and important to the free and open source software community, many users wish to be sure about the origin of the package and its content before installing the package. There are two verification methods that can be used independently from each other to prove the authenticity of a downloaded file or rpm package: 1) md5sums as provided in the (cryptographically signed) announcement. 2) using the internal gpg signatures of the rpm package. 1) execute the command md5sum <name-of-the-file.rpm> after you downloaded the file from a SuSE ftp server or its mirrors. Then, compare the resulting md5sum with the one that is listed in the announcement. Since the announcement containing the checksums is cryptographically signed (usually using the key security@suse.de), the checksums show proof of the authenticity of the package. We disrecommend to subscribe to security lists which cause the email message containing the announcement to be modified so that the signature does not match after transport through the mailing list software. Downsides: You must be able to verify the authenticity of the announcement in the first place. If RPM packages are being rebuilt and a new version of a package is published on the ftp server, all md5 sums for the files are useless. 2) rpm package signatures provide an easy way to verify the authenticity of an rpm package. Use the command rpm -v --checksig <file.rpm> to verify the signature of the package, where <file.rpm> is the filename of the rpm package that you have downloaded. Of course, package authenticity verification can only target an uninstalled rpm package file. Prerequisites: a) gpg is installed b) The package is signed using a certain key. The public part of this key must be installed by the gpg program in the directory ~/.gnupg/ under the user's home directory who performs the signature verification (usually root). You can import the key that is used by SuSE in rpm packages for SuSE Linux by saving this announcement to a file ("announcement.txt") and running the command (do "su -" to be root): gpg --batch; gpg < announcement.txt | gpg --import SuSE Linux distributions version 7.1 and thereafter install the key "build@suse.de" upon installation or upgrade, provided that the package gpg is installed. The file containing the public key is placed at the toplevel directory of the first CD (pubring.gpg) and at ftp://ftp.suse.com/pub/suse/pubring.gpg-build.suse.de . - SuSE runs two security mailing lists to which any interested party may subscribe: suse-security@suse.com - general/linux/SuSE security discussion. All SuSE security announcements are sent to this list. To subscribe, send an email to <suse-security-subscribe@suse.com>. suse-security-announce@suse.com - SuSE's announce-only mailing list. Only SuSE's security annoucements are sent to this list. To subscribe, send an email to <suse-security-announce-subscribe@suse.com>. For general information or the frequently asked questions (faq) send mail to: <suse-security-info@suse.com> or <suse-security-faq@suse.com> respectively. =================================================== SuSE's security contact is <security@suse.com>. The <security@suse.com> public key is listed below. =================================================== ______________________________________________________________________________ The information in this advisory may be distributed or reproduced, provided that the advisory is not modified in any way. In particular, it is desired that the cleartext signature shows proof of the authenticity of the text. SuSE GmbH makes no warranties of any kind whatsoever with respect to the information contained in this security advisory. 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