__________________________________________________________ The U.S. Department of Energy Computer Incident Advisory Center ___ __ __ _ ___ / | /_\ / \___ __|__ / \ \___ __________________________________________________________ INFORMATION BULLETIN SuSE Linux, xinetd Buffer Overflow July 3, 2001 21:00 GMT Number L-104 ______________________________________________________________________________ PROBLEM: SuSE Linux, xinetd has a buffer overflow vulnerability PLATFORM: i386 Intel Platform: SuSE-6.3,6.4,7.0, 7.1, 7.2 Sparc Platform: SuSE-7.1 AXP Alpha Platform: SuSE-6.3,6.4,7.0, 7.1 PPC Power PC Platform: SuSE-6.4,7.0, 7.1 DAMAGE: The buffer overflow vulnerability allows a remote attacker to execute arbitrary code at all privleges. SOLUTION: Apply patches supplied by SuSE ______________________________________________________________________________ VULNERABILITY The risk is HIGH. The vulnerability results in a root ASSESSMENT: compromise, it is remotely exploitable, and is widely publicized. ______________________________________________________________________________ [****** Start SuSE Advisory ******] SuSE Security Announcement: xinetd (SuSE-SA:2001:022) -----BEGIN PGP SIGNED MESSAGE----- ______________________________________________________________________________ SuSE Security Announcement Package: xinetd Announcement-ID: SuSE-SA:2001:022 Date: Friday, June 29th 2001, 13:26:55 CEST Affected SuSE versions: (6.0, 6.1, 6.2), 6.3, 6.4, 7.0, 7.1, 7.2 Vulnerability Type: remote code execution Severity (1-10): 7 SuSE default package: yes Other affected systems: All systems using xinetd Content of this advisory: 1) security vulnerability resolved: xinetd buffer-overflows 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 Zen-parse has reported a bug to Bugtraq which allows remote attackers to overflow a buffer in the logging routine of xinetd. During investigation we found that more problems exist within xinetd. Xinetd provides its own string-handling (snprintf()-like functions) routines and fails to handle length arguments of 0 properly. Instead of an immediate return it assumes 'no limit' for writing characters to the target-buffer. This can lead to overflows and arbitrary remote code-execution. Additionally xinetd now sets the correct umask before starting other deamons. Please update the packages immediately, kill the old deamon and start the new xinetd deamon with the /etc/rc.d/xinetd start command again if you need it running. Regardless of the bugs in xinetd, please make sure you only run as many services as needed. i386 Intel Platform: SuSE-7.2 ftp://ftp.suse.com/pub/suse/i386/update/7.2/n2/xinetd-2.1.8.8p3-139.i386.rpm a8122710a857e49a356b0786c8aad9eb source rpm: ftp://ftp.suse.com/pub/suse/i386/update/7.2/zq1/xinetd-2.1.8.8p3-139.src.rpm 90187bd35f931f07ba72b54c16c1549c SuSE-7.1 ftp://ftp.suse.com/pub/suse/i386/update/7.1/n2/xinetd-2.1.8.8p3-140.i386.rpm 346868fe76e17d17d87dadbac4c032bb source rpm: ftp://ftp.suse.com/pub/suse/i386/update/7.1/zq1/xinetd-2.1.8.8p3-140.src.rpm 6656be9789888da5b1b37dc1aa9c69a9 SuSE-7.0 ftp://ftp.suse.com/pub/suse/i386/update/7.0/n1/xinetd-2.1.8.8p3-140.i386.rpm ff001b856db620213608dac1c88ebfbe source rpm: ftp://ftp.suse.com/pub/suse/i386/update/7.0/zq1/xinetd-2.1.8.8p3-140.src.rpm 627d2f09d9d4607f31e1902eee4e0cb5 SuSE-6.4 ftp://ftp.suse.com/pub/suse/i386/update/6.4/n1/xinetd-2.1.8.8p3-139.i386.rpm ef4697d57a6ceb5e6a55bde51268b92a source rpm: ftp://ftp.suse.com/pub/suse/i386/update/6.4/zq1/xinetd-2.1.8.8p3-139.src.rpm 1384b48ed19204324d4a8c2f75d3ea20 SuSE-6.3 ftp://ftp.suse.com/pub/suse/i386/update/6.3/n1/xinetd-2.1.8.8p3-141.i386.rpm 3c29917f0688aa7509f98b0a00a38eed source rpm: ftp://ftp.suse.com/pub/suse/i386/update/6.3/zq1/xinetd-2.1.8.8p3-141.src.rpm b7f8cc1e5a7d3c2f6c56040c327a4b20 Sparc Platform: SuSE-7.1 ftp://ftp.suse.com/pub/suse/sparc/update/7.1/n2/xinetd-2.1.8.8p3-89.sparc.rpm a78dd53e2da211b8822b4ca86359a6e0 source rpm: ftp://ftp.suse.com/pub/suse/sparc/update/7.1/zq1/xinetd-2.1.8.8p3-89.src.rpm 9b0acb0dacee2962f19057de43d9f421 AXP Alpha Platform: SuSE-7.1 ftp://ftp.suse.com/pub/suse/axp/update/7.1/n2/xinetd-2.1.8.8p3-96.alpha.rpm bb2b45d56d2cf54733a20561c8a8e440 source rpm: ftp://ftp.suse.com/pub/suse/axp/update/7.1/zq1/xinetd-2.1.8.8p3-96.src.rpm 60610276aba8c103a43a40ea0366f675 SuSE-7.0 ftp://ftp.suse.com/pub/suse/axp/update/7.0/n1/xinetd-2.1.8.8p3-96.alpha.rpm 1e4f0685f380db64025837685f8e79c2 source rpm: ftp://ftp.suse.com/pub/suse/axp/update/7.0/zq1/xinetd-2.1.8.8p3-96.src.rpm addfd497500387b4de4e2c77ff226e01 SuSE-6.4 ftp://ftp.suse.com/pub/suse/axp/update/6.4/n1/xinetd-2.1.8.8p3-95.alpha.rpm f39287594d3297d2625f3878be6b7d98 source rpm: ftp://ftp.suse.com/pub/suse/axp/update/6.4/zq1/xinetd-2.1.8.8p3-95.src.rpm ea727667791cd774a5df8bcb5b8b2870 SuSE-6.3 ftp://ftp.suse.com/pub/suse/axp/update/6.3/n1/xinetd-2.1.8.8p3-95.alpha.rpm 364120a5e0ba13587efba8c082faafa0 source rpm: ftp://ftp.suse.com/pub/suse/axp/update/6.3/zq1/xinetd-2.1.8.8p3-95.src.rpm 08c540c506809a9a5b080aa21fe97406 PPC Power PC Platform: SuSE-7.1 ftp://ftp.suse.com/pub/suse/ppc/update/7.1/n2/xinetd-2.1.8.8p3-102.ppc.rpm b73446661fe3f5967acd0242e83fb815 source rpm: ftp://ftp.suse.com/pub/suse/ppc/update/7.1/zq1/xinetd-2.1.8.8p3-102.src.rpm c89cb923d3c837e50e7f2efc2c9708d2 SuSE-7.0 ftp://ftp.suse.com/pub/suse/ppc/update/7.0/n1/xinetd-2.1.8.8p3-101.ppc.rpm 01fec52a269c456636bcda0d8401b639 source rpm: ftp://ftp.suse.com/pub/suse/ppc/update/7.0/zq1/xinetd-2.1.8.8p3-101.src.rpm f91f365e3cbedc3de52aab7667db97b2 SuSE-6.4 ftp://ftp.suse.com/pub/suse/ppc/update/6.4/n1/xinetd-2.1.8.8p3-101.ppc.rpm ed8e343b428fe812502195a15d9c4219 source rpm: ftp://ftp.suse.com/pub/suse/ppc/update/6.4/zq1/xinetd-2.1.8.8p3-101.src.rpm a340276cec8a5dedcbcd29e199bef6a1 ______________________________________________________________________________ 2) Pending vulnerabilities in SuSE Distributions and Workarounds: - rxvt The rxvt program contains a buffer-overflow which allows an attacker to locally execute arbitrary code under a different group-id. Please update to the newest rxvt packages. - dqs The dsh-program, shipped with the dqs package contains a buffer-overflow which allows local attackers to execute arbitrary code as root. Please update to the newest packages. - pcp A /tmp - race has been found in the pcp package which allows a local attacker to escalate his priviledges. Affected versions: 7.1, 7.2. We thank Mark Goodwin and Keith Owens from SGI who quickly responded to SuSE in this issue and who released a fixed version of the SGI Performance Co-Pilot in response to the security problem. Future SuSE Linux releases will include the most recent version of the package. Workaround: chmod a-s `rpm -ql pcp` /nosuchfile update-package does the same. ______________________________________________________________________________ 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 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 to verify the signature of the package, where 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-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 . For general information or the frequently asked questions (faq) send mail to: or respectively. =================================================== SuSE's security contact is . The 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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CIAC is located at the Lawrence Livermore National Laboratory in Livermore, California. CIAC is also a founding member of FIRST, the Forum of Incident Response and Security Teams, a global organization established to foster cooperation and coordination among computer security teams worldwide. CIAC services are available to DOE, DOE contractors, and the NIH. CIAC can be contacted at: Voice: +1 925-422-8193 (7x24) FAX: +1 925-423-8002 STU-III: +1 925-423-2604 E-mail: ciac@ciac.org Previous CIAC notices, anti-virus software, and other information are available from the CIAC Computer Security Archive. World Wide Web: http://www.ciac.org/ Anonymous FTP: ftp.ciac.org PLEASE NOTE: Many users outside of the DOE, ESnet, and NIH computing communities receive CIAC bulletins. If you are not part of these communities, please contact your agency's response team to report incidents. Your agency's team will coordinate with CIAC. The Forum of Incident Response and Security Teams (FIRST) is a world-wide organization. A list of FIRST member organizations and their constituencies can be obtained via WWW at http://www.first.org/. This document was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor the University of California nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial products, process, or service by trade name, trademark, manufacturer, or otherwise, does not necessarily constitute or imply its endorsement, recommendation or favoring by the United States Government or the University of California. 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