-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 ______________________________________________________________________________ Caldera Systems, Inc. Security Advisory Subject: DoS attack against named Advisory number: CSSA-2000-040.0 Issue date: 2000 November, 10 Cross reference: ______________________________________________________________________________ 1. Problem Description There's a bug in named's handling of compressed zone transfers (ZXFR) that causes it to crash under certain circumstances. At the very least, this is a denial of service attack. As the bug is still being investigated, it cannot be ruled out that this bug has a more severe security impact. This bug affects you _only_ if you are running named, and act as the primary name server for one or more zones. If does not affect you if you merely run named in forwarding mode. 2. Vulnerable Versions System Package ----------------------------------------------------------- OpenLinux Desktop 2.3 All packages previous to bind-8.2.2p7-1 OpenLinux eServer 2.3 All packages previous to and OpenLinux eBuilder bind-8.2.2p7-1 OpenLinux eDesktop 2.4 All packages previous to bind-8.2.2p7-1 3. Solution Workaround: As a minimum, you should restrict zone transfers to those hosts that actually act as your secondary name servers. You can do this by adding an "allow-transfer" statement to each zone you act as a primary for. For instance, zone "foobar.com" { type master; file "foobar.com"; allow-transfer { 192.168.1.1; 192.168.3.17 }; } This will not completely protect you from the ZXFR attack, but now the only sites able to perform it are those listed in the allow-transfer clause. 4. OpenLinux Desktop 2.3 4.1 Location of Fixed Packages The upgrade packages can be found on Caldera's FTP site at: ftp://ftp.calderasystems.com/pub/updates/OpenLinux/2.3/current/RPMS/ The corresponding source code package can be found at: ftp://ftp.calderasystems.com/pub/updates/OpenLinux/2.3/current/SRPMS 4.2 Verification 9d8429f25c5fb3bebe2d66b1f9321e61 RPMS/bind-8.2.2p7-1.i386.rpm 0e958eb01f40826f000d779dbe6b8cb3 RPMS/bind-doc-8.2.2p7-1.i386.rpm 866ff74c77e9c04a6abcddcc11dbe17b RPMS/bind-utils-8.2.2p7-1.i386.rpm 6a545924805effbef01de74e34ba005e SRPMS/bind-8.2.2p7-1.src.rpm 4.3 Installing Fixed Packages Upgrade the affected packages with the following commands: rpm -Fhv bind-*.i386.rpm 5. OpenLinux eServer 2.3 and OpenLinux eBuilder for ECential 3.0 5.1 Location of Fixed Packages The upgrade packages can be found on Caldera's FTP site at: ftp://ftp.calderasystems.com/pub/updates/eServer/2.3/current/RPMS/ The corresponding source code package can be found at: ftp://ftp.calderasystems.com/pub/updates/eServer/2.3/current/SRPMS 5.2 Verification 379c4328604b4491a8f3d0de44e42347 RPMS/bind-8.2.2p7-1.i386.rpm b428b824c8b67f2d8d4bf53738a3e7e0 RPMS/bind-doc-8.2.2p7-1.i386.rpm 28311d630281976a870d38abe91f07fb RPMS/bind-utils-8.2.2p7-1.i386.rpm 6a545924805effbef01de74e34ba005e SRPMS/bind-8.2.2p7-1.src.rpm 5.3 Installing Fixed Packages Upgrade the affected packages with the following commands: rpm -Fhv bind-*.i386.rpm 6. OpenLinux eDesktop 2.4 6.1 Location of Fixed Packages The upgrade packages can be found on Caldera's FTP site at: ftp://ftp.calderasystems.com/pub/updates/eDesktop/2.4/current/RPMS/ The corresponding source code package can be found at: ftp://ftp.calderasystems.com/pub/updates/eDesktop/2.4/current/SRPMS 6.2 Verification c37b6673cc9539e592013ac114846940 RPMS/bind-8.2.2p7-1.i386.rpm bbe0d7e317fde0d47cba1384f6d4b635 RPMS/bind-doc-8.2.2p7-1.i386.rpm 5c28dd5641a4550c03e9859d945a806e RPMS/bind-utils-8.2.2p7-1.i386.rpm 6a545924805effbef01de74e34ba005e SRPMS/bind-8.2.2p7-1.src.rpm 6.3 Installing Fixed Packages Upgrade the affected packages with the following commands: rpm -Fhv bind-*.i386.rpm 7. References This and other Caldera security resources are located at: http://www.calderasystems.com/support/security/index.html This security fix closes Caldera's internal Problem Report 8230. 8. Disclaimer Caldera Systems, Inc. is not responsible for the misuse of any of the information we provide on this website and/or through our security advisories. Our advisories are a service to our customers intended to promote secure installation and use of Caldera OpenLinux. ______________________________________________________________________________ -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.0.4 (GNU/Linux) Comment: For info see http://www.gnupg.org iD8DBQE6DAn118sy83A/qfwRAiiBAKC/0WNCkfDJoHDjfuMgY1mQFWZ4awCgisAp dhuUp0QpTBKLAN15sdIadPE= =3IEb -----END PGP SIGNATURE-----