-----BEGIN PGP SIGNED MESSAGE----- ______________________________________________________________________________ SuSE Security Announcement Package: shadow/login Announcement-ID: SuSE-SA:2001:034 Date: Tuesday, Oct 23rd 2001 18:00 MEST Affected SuSE versions: 6.3, 6.4, 7.0, 7.1, 7.2, 7.3 Vulnerability Type: local privilege escalation Severity (1-10): 2 SuSE default package: yes Other affected systems: most linux systems, common problem on linux-like systems. Content of this advisory: 1) security vulnerability resolved: shadow/login 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 Multiple Linux vendors have issued security announcements about failures of the /bin/login program to properly initialize the privileges of an authenticated user if the PAM module pam_limits is enabled. The bug has been categorized as a sequence bug, and is located in the code of the login program itself: A call to getpwnam(3) returns a pointer to a struct passwd, and the data is being used. Then, a call to PAM routines cause getpwnam(3) to be called again, but beyond the programmer's control or knowledge. The pointer as returned by the first getpwnam(3) remains the same, but the data may be different. By consequence, the data is in an undefined state. The error appears with the pam_limits PAM module only because other PAM modules do not call getpwnam(3). SuSE developers did not succeed in reproducing the error on SuSE Linux installations since SuSE distributions do not come with the standard login implementation from the util-linux collection. Instead, a version maintained by Thorsten Kukuk <kukuk@suse.de> is used. This login implementation may cause wrong group IDs to be set in very rare cases. The harm of this bug is therefore considerably small on SuSE Linux. However, we provide fixed rpm packages that remedy the problem. Since the bug is not limited to the login program but to all programs that authenticate users, more security announcements in this field are to be expected. The Linux vendors cooperate to share the workload that results from the audit of these programs. To install the updates, please download the update package for your distribution and use the command 'rpm -Uhv file.rpm' to apply the update. Please run "SuSEconfig" after performing the package update to make sure that the permissions of your files are configured as the security settings of your installation define. Alternatively, if you have disabled SuSEconfig, check for the permissions of the files /usr/bin/chage, /usr/bin/chfn, /usr/bin/chsh, /usr/bin/expiry, /usr/bin/gpasswd and /usr/bin/passwd to suit your needs. Setting these executeables to 4755 owned by root enables their functionality, removing the setuid bit (chmod -s) disables it. i386 Intel Platform: SuSE-7.3 ftp://ftp.suse.com/pub/suse/i386/update/7.3/a1/shadow-20000902-144.i386.rpm 9380496a4a248aeac73d7136de381348 source rpm: ftp://ftp.suse.com/pub/suse/i386/update/7.3/zq1/shadow-20000902-144.src.rpm b595cea811bb92aa895974aee2fd5968 SuSE-7.2 ftp://ftp.suse.com/pub/suse/i386/update/7.2/a1/shadow-20000902-145.i386.rpm 18e33d4b728b49403c2679c560b52f06 source rpm: ftp://ftp.suse.com/pub/suse/i386/update/7.2/zq1/shadow-20000902-145.src.rpm 0d9fb9cec79cdd4671306658a103fc6b SuSE-7.1 ftp://ftp.suse.com/pub/suse/i386/update/7.1/a1/shadow-20000902-145.i386.rpm a5b2177d66048f988249e0acbc9648bf source rpm: ftp://ftp.suse.com/pub/suse/i386/update/7.1/zq1/shadow-20000902-145.src.rpm 4525572bf268b73004774a25d7f5de2a SuSE-7.0 ftp://ftp.suse.com/pub/suse/i386/update/7.0/a1/shadow-19990827-170.i386.rpm 2be3765b08ce9d94abbd4932dbe3f39b source rpm: ftp://ftp.suse.com/pub/suse/i386/update/7.0/zq1/shadow-19990827-170.src.rpm 97935450371dde96cb92134ab8596b85 SuSE-6.4 ftp://ftp.suse.com/pub/suse/i386/update/6.4/a1/shadow-19990827-145.i386.rpm c6d07aa8662e00d501f9fbb9d57f71bb source rpm: ftp://ftp.suse.com/pub/suse/i386/update/6.4/zq1/shadow-19990827-145.src.rpm 79d9e99e67fcd23d64508eafe5070b36 SuSE-6.3 ftp://ftp.suse.com/pub/suse/i386/update/6.3/a1/shadow-19990827-145.i386.rpm 82c4466697251685c5f1fa733c0ad4e2 source rpm: ftp://ftp.suse.com/pub/suse/i386/update/6.3/zq1/shadow-19990827-145.src.rpm bac32336670e134146af62886e3d477e Sparc Platform: SuSE-7.1 ftp://ftp.suse.com/pub/suse/sparc/update/7.1/a1/shadow-20000902-92.sparc.rpm 3e63326bd5dd2dd3e9d8175b6db918e0 source rpm: ftp://ftp.suse.com/pub/suse/sparc/update/7.1/zq1/shadow-20000902-92.src.rpm c95b2761cc4d9b417394a550d43716ca SuSE-7.0 ftp://ftp.suse.com/pub/suse/sparc/update/7.0/a1/shadow-19990827-2.sparc.rpm 5ce1d42bb0e5a6677666390b9980de5d source rpm: ftp://ftp.suse.com/pub/suse/sparc/update/7.0/zq1/shadow-19990827-2.src.rpm 622dc8e8c6d6bf90f09d79b144a20533 AXP Alpha Platform: SuSE-7.1 ftp://ftp.suse.com/pub/suse/axp/update/7.1/a1/shadow-20000902-88.alpha.rpm ed882226bcb5241e105fb0f6466bf476 source rpm: ftp://ftp.suse.com/pub/suse/axp/update/7.1/zq1/shadow-20000902-88.src.rpm b70743683ca521d66be357b90baff035 SuSE-7.0 ftp://ftp.suse.com/pub/suse/axp/update/7.0/a1/shadow-19990827-74.alpha.rpm 778ebfcaacc9087e6c781f6a10a68a75 source rpm: ftp://ftp.suse.com/pub/suse/axp/update/7.0/zq1/shadow-19990827-74.src.rpm 68d957bf5d0cc942e12501056d05f0bd SuSE-6.4 ftp://ftp.suse.com/pub/suse/axp/update/6.4/a1/shadow-19990827-74.alpha.rpm e7646c335fa009506535412daf344480 source rpm: ftp://ftp.suse.com/pub/suse/axp/update/6.4/zq1/shadow-19990827-74.src.rpm 3d748914265b37b15b42687e5ff87945 SuSE-6.3 ftp://ftp.suse.com/pub/suse/axp/update/6.3/a1/shadow-19990827-74.alpha.rpm c1cb80bb6d7a15a445550c739ced029b source rpm: ftp://ftp.suse.com/pub/suse/axp/update/6.3/zq1/shadow-19990827-74.src.rpm 0b05d59fffc9ff8bd1cb922df7a84fac PPC Power PC Platform: SuSE-7.1 ftp://ftp.suse.com/pub/suse/ppc/update/7.1/a1/shadow-20000902-61.ppc.rpm a1dbc8bb966db28469fabe583d157bed source rpm: ftp://ftp.suse.com/pub/suse/ppc/update/7.1/zq1/shadow-20000902-61.src.rpm 2b2f0fbcb842149cb095fff125f54279 SuSE-7.0 ftp://ftp.suse.com/pub/suse/ppc/update/7.0/a1/shadow-19990827-182.ppc.rpm d55986fc84158f06dcbfea0c7812037f source rpm: ftp://ftp.suse.com/pub/suse/ppc/update/7.0/zq1/shadow-19990827-182.src.rpm dc84f0301b4a4daeae1fb6465f0d16c1 SuSE-6.4 ftp://ftp.suse.com/pub/suse/ppc/update/6.4/a1/shadow-19990827-182.ppc.rpm 3d7e644c70e6d98944ff623b24bbfde0 source rpm: ftp://ftp.suse.com/pub/suse/ppc/update/6.4/zq1/shadow-19990827-182.src.rpm 646985dc82d9845832db6863fba9442d ______________________________________________________________________________ 2) Pending vulnerabilities in SuSE Distributions and Workarounds: - Linux kernel Security bugs have been found in both the 2.2 and 2.4 kernel series of all currently supported SuSE Linux distributions (6.3-7.3), including the freshly appeared SuSE-7.3. These bugs allow a local attacker to gain root privileges, but there is no remote attack as of now. As a temporary workaround, it is possible for experienced users of linux-like systems to disable all setuid bits from all files in the installed system using a find command with a -exec option. We are currently in the process of testing the update kernels of both 2.2 (2.2.19) and 2.4 (2.4.13) series to make sure that these update kernels will have the same level of stability and robustness as expected from SuSE linux systems. The official kernel rpm packages will be announced in a SuSE Security announcement during the second half of this week. In the meanwhile, the directory ftp://ftp.suse.com/pub/people/mantel/next/ contains the preliminary update packages for testing (2.2.19 packages will be available shortly). Please proceed with the update as described in http://www.suse.de/de/support/security/2001_018_kernel_txt.txt and report any problems that you may find to feedback@suse.de. - openssh After stabilizing the openssh package, updates for the distributions 6.4-7.2 are currently being prepared. The update packages fix a security problem related to the recently discovered problems with source ip based access restrictions in a user's ~/.ssh/authorized_keys2 file. The packages will appear shortly on our ftp servers. Please note that packages for the distributions 6.3 and up including 7.0 containing cryptographic software are located on the German ftp server ftp.suse.de, all other packages can be found on ftp.suse.com at the usual location. - htdig (ht://Dig) htdig, a powerful indexing and information gathering tool for a webserver, has been found vulnerable to a weakness where commandline options can be passed on to the cgi program as a result of weak runtime environment checking. The security announcement by Thomas Biege is waiting for the update packages to reach the ftp-server (currently transferring). Please continue to watch the suse-security-announce mailing list for new security announcements. ______________________________________________________________________________ 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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