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SuSE: 2002:026 Moderate: BIND Buffer Overflow Threat Advisory

A vulnerability has been discovered in some resolver library functions. The affected code goes back to the resolver library shipped as part of BIND4; code derived from it has been included in later BIND releases as well as the GNU libc.. ______________________________________________________________________________ SuSE Security Announcement Package: bind, glibc Announcement-ID: SuSE-SA:2002:026 Date: Tue Jul 09 2002 Affected products: 7.0, 7.1, 7.2, 7.3, 8.0 SuSE Linux Enterprise Server for S/390, SuSE Linux Database Server, SuSE eMail Server III, SuSE Linux Enterprise Server, SuSE Linux Firewall on CD Vulnerability Type: buffer overflow Severity (1-10): 3 SuSE default package: yes Cross References: CERT CA-2002-19; CVE CAN-2002-0651 Content of this advisory: 1) security vulnerability resolved: buffer overflow in dig, host, and nslookup utilities. 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 A vulnerability has been discovered in some resolver library functions. The affected code goes back to the resolver library shipped as part of BIND4; code derived from it has been included in later BIND releases as well as the GNU libc. The bug itself is a buffer overflow that can be triggered if a DNS server sends multiple CNAME records in a DNS response. This bug has been fixed for the gethostbyXXX class of functions in GNU libc in 1999. Unfortunately, there is similar code in the getnetbyXXX functions in recent glibc implementations, and the code is enabled by default. However, these functions are thecode is enabled by default. However, these functions are used by very few applications only, such as ifconfig and ifuser, which makes exploits less likely. We will make updated glibc packages available as they have gone through our build system, but without separate announcements. Until glibc patches are available, we recommend that you disable DNS lookups of network names in nsswitch.conf. Simply replace the line containing the tag "networks:" with this line: networks: files In the unlikely event that you've configured any name to network mapping via DNS, make sure you copy this information to /etc/networks. The resolver bug is also present in the libbind library included in BIND. This library is used by utilities from the bindutil package. We are therefore providing security updates for bind8 that address this vulnerability. As communicated previously (1), the SuSE security team is not providing fixes for BIND4 anymore. The bind9 packages shipped by SuSE are not vulnerable. Please download the update package for your distribution and verify its integrity by the methods listed in section 3) of this announcement. Apply the updata packages (bindutil, bind8) package using rpm -Fvh bind*.rpm If you are running the BIND name server, you should restart the name server process by issuing rcnamed restart Our maintenance customers are being notified individually. The packages are being offered to install from the maintenance web. References: (1) SUSE – Open-Source-Lösungen für Enterprise Server und Cloud | SUSE (1) SUSE – Open-Source-Lösungen für Enterprise Server und Cloud | SUSE ______________________________________________________________________________ 2) Pending vulnerabilities in SuSE Distributions and Workarounds: - There is a format string bug in the "nn" news reader that can be exploited by a malicious NNTP server to execute arbitrary commands within theclient user's account. We will be releasing updated packages. ______________________________________________________________________________ 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 This email address is being protected from spambots. You need JavaScript enabled to view it. ), 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 havedownloaded. 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 " This email address is being protected from spambots. You need JavaScript enabled to view it. " 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 . - SuSE runs two security mailing lists to which any interested party may subscribe: This email address is being protected from spambots. You need JavaScript enabled to view it. - general/linux/SuSE security discussion. All SuSE security announcements are sent to this list. To subscribe, send an email to . This email address is being protected from spambots. You need JavaScript enabled to view it. - 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. respectively. ==================================================================== SuSE's security contact is or . The public key is listed below. ====================================================================______________________________________________________________________________ The information in thisadvisory 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 Linux AG makes no warranties of any kind whatsoever with respect to the information contained in this security advisory. Type Bits/KeyID Date User ID pub 2048R/3D25D3D9 1999-03-06 SuSE Security Team pub 1024D/9C800ACA 2000-10-19 SuSE Package Signing Key . An important memory overflow flaw in Bind and Glibc present on SUSE Linux may allow cybercriminals to run malicious code, jeopardizing the security of the system.. SUSE Linux Security, Glibc Threat, Bind Update. . LinuxSecurity.com Team

Jul 09, 2002 SuSE