+---------------------------------------------------------------------+ | LinuxSecurity.com Weekly Newsletter | | July 9, 2004 Volume 5, Number 27a | +---------------------------------------------------------------------+ Editors: Dave Wreski Benjamin Thomas dave@xxxxxxxxxxxxxxxxx ben@xxxxxxxxxxxxxxxxx Linux Advisory Watch is a comprehensive newsletter that outlines the security vulnerabilities that have been announced throughout the week. It includes pointers to updated packages and descriptions of each vulnerability. This week, advisories were released for webmin, pavuk, kernel, mailman, rsync, Esearch, Apache, XFree86, libpng, Shorewall, tripwire and httpd. The distributors include Debian, Fedora, FreeBSD, Gentoo, Mandrake, Red Hat and Suse. ----- >> Need to Secure Multiple Domain or Host Names? << Securing multiple domain or host names need not burden you with unwanted administrative hassles. Learn more about how the cost-effective Thawte Starter PKI program can streamline management of your digital certificates. Click here to download our Free guide: http://ads.linuxsecurity.com/cgi-bin/newad_redirect.pl?id=thawte07 ----- Kerberos, Part I Introduction Kerberos is an authentication system developed by the Athena Project at MIT. When a user logs in, Kerberos authenticates that user (using a password), and provides the user with a way to prove her identity to other servers and hosts scattered around the network. This authentication is then used by programs such as rlogin to allow the user to login to other hosts without a password (in place of the .rhosts file). This authentication method can also used by the mail system in order to guarantee that mail is delivered to the correct person, as well as to guarantee that the sender is who he claims to be. The overall effect of installing Kerberos and the numerous other programs that go with it is to virtually eliminate the ability of users to "spoof" the system into believing they are someone else. Unfortunately, installing Kerberos is very intrusive, requiring the modification or replacement of numerous standard programs. Implementation Implementing Kerberos on the client isn't too difficult, however, it's a different story implementing a server. The document The Moron's Guide to Kerberos does a good job of explaining Kerberos in more detail, as well as guiding users and administrators through the process of creating and using the server. It is available at the following URL: http://www.isi.edu/gost/brian/security/kerberos.html Most distributions include support for Kerberos. Distributions that use PAM are much easier to configure. Applications normally require recompiling to support using Kerberos as the authentication mechanism, but PAM resolves those issues by allowing you to 'plug-in' a Kerberos authentication module. Kerberos isn't for everyone. Install the client support for your distribution if you require it to connect to a Kerberos server on your network. Install the Kerberos server if you have to support a large number of distributed clients and require the extra authentication. Generally, using the Secure Shell is a fine alternative for authenticating users before logging into remote machines or transferring files. Next week, we will explore how Kerberos actually works. Security Tip Written by Dave Wreski (ben@xxxxxxxxxxxxxxxxxxx) Additional tips are available at the following URL: http://www.linuxsecurity.com/tips/ ----- Open Source Leaving Microsoft Sitting on the Fence? The open source model, with special regard to Linux, has no doubt become a formidable competitor to the once sole giant of the software industry, Microsoft. It is expected when the market share of an industry leader becomes threatened, retaliation with new product or service offerings and marketing campaigns refuting the claims of the new found competition are inevitable. However, in the case of Microsoft, it seems they have not taken a solid or plausible position on the use of open source applications as an alternative to Windows. http://www.linuxsecurity.com/feature_stories/feature_story-168.html -------------------------------------------------------------------- Guardian Digital Launches Next Generation Secure Mail Suite Guardian Digital, the premier open source security company, announced the availability of the next generation Secure Mail Suite, the industry's most secure open source corporate email system. This latest edition has been optimized to support the changing needs of enterprise and small business customers while continually providing protection from the latest in email security threats. http://www.linuxsecurity.com/feature_stories/feature_story-166.html -------------------------------------------------------------------- --> Take advantage of the LinuxSecurity.com Quick Reference Card! --> http://www.linuxsecurity.com/docs/QuickRefCard.pdf +---------------------------------+ | Distribution: Debian | ----------------------------// +---------------------------------+ 7/8/2004 - webmin Multiple vulnerabilities This patch addresses an ACL bypass and the ability to use brute force to get IDs and passwords. http://www.linuxsecurity.com/advisories/debian_advisory-4548.html 7/8/2004 - pavuk Buffer overflow vulnerability An oversized HTTP 305 response sent by a malicious server could cause arbitrary code to be executed with the privileges of the pavuk process. http://www.linuxsecurity.com/advisories/debian_advisory-4549.html +---------------------------------+ | Distribution: Fedora: | ----------------------------// +---------------------------------+ 7/2/2004 - kernel Privilege change vulnerability During an audit of the Linux kernel, SUSE discovered a flaw in the Linux kernel that inappropriately allows an unprivileged user to change the group ID of a file to his/her own group ID. http://www.linuxsecurity.com/advisories/fedora_advisory-4532.html 7/2/2004 - mailman Password leak vulnerability Mailman subscriber passwords could be retrieved by a remote attacker. http://www.linuxsecurity.com/advisories/fedora_advisory-4533.html 7/2/2004 - rsync Path escape vulnerability A writing, non-chrooted rsync daemon could write outside of a module's path. http://www.linuxsecurity.com/advisories/fedora_advisory-4534.html 7/8/2004 - kernel Corrected md5 sums This posting gives the correct md5 sums for the previous kernel update. http://www.linuxsecurity.com/advisories/fedora_advisory-4547.html +---------------------------------+ | Distribution: FreeBSD | ----------------------------// +---------------------------------+ 7/2/2004 - kernel Improper memory access vulnerability It may be possible for a local attacker to read and/or overwrite portions of kernel memory, resulting in disclosure of sensitive information or potential privilege escalation. http://www.linuxsecurity.com/advisories/freebsd_advisory-4531.html +---------------------------------+ | Distribution: Gentoo | ----------------------------// +---------------------------------+ 7/2/2004 - Esearch Insecure temp file vulnerability Non-check for symlinks makes it possible for any user to create arbitrary files. http://www.linuxsecurity.com/advisories/gentoo_advisory-4530.html 7/8/2004 - kernel Multiple vulnerabilities This patch addresses a large number of kernel vulnerabilities. http://www.linuxsecurity.com/advisories/gentoo_advisory-4541.html 7/8/2004 - Apache 2 Denial of service vulnerability A remote attacker to perform a Denial of Service attack and possible heap based buffer overflow. http://www.linuxsecurity.com/advisories/gentoo_advisory-4542.html 7/8/2004 - Pure-FTPd Denial of service vulnerability 2 Denial of service vulnerability Pure-FTPd contains a bug potentially allowing a Denial of Service attack when the maximum number of connections is reached. http://www.linuxsecurity.com/advisories/gentoo_advisory-4543.html 7/8/2004 - XFree86 Improper access vulnerability This bug may allow authorized users to access a machine remotely via X, even if the administrator has configured XDM to refuse such connections. http://www.linuxsecurity.com/advisories/gentoo_advisory-4544.html 7/8/2004 - libpng Buffer overflow vulnerability Vulnerability allows attacker to perform a Denial of Service attack or even execute arbitrary code. http://www.linuxsecurity.com/advisories/gentoo_advisory-4545.html 7/8/2004 - Shorewall Insecure temp file vulnerability This can allow a non-root user to overwrite arbitrary system files. http://www.linuxsecurity.com/advisories/gentoo_advisory-4546.html +---------------------------------+ | Distribution: Mandrake | ----------------------------// +---------------------------------+ 7/8/2004 - tripwire Format string vulnerability A format string vulnerability in tripwire could allow a local user to execute arbitrary code with the rights of the user running tripwire (typically root). http://www.linuxsecurity.com/advisories/mandrake_advisory-4539.html 7/8/2004 - kernel Multiple vulnerabilities This patch addresses a large number of vulnerabilities, uncluding the ability for a user to set the gid of arbitrary files. http://www.linuxsecurity.com/advisories/mandrake_advisory-4540.html +---------------------------------+ | Distribution: Red Hat | ----------------------------// +---------------------------------+ 7/8/2004 - kernel (e-3) File metadata change vulnerability Using NFS, a user could make unauthrized changes to files' GID. http://www.linuxsecurity.com/advisories/redhat_advisory-4536.html 7/8/2004 - kernel (e-2.1) File metadata change vulnerability Using NFS, a user could make unauthrized changes to files' GID. http://www.linuxsecurity.com/advisories/redhat_advisory-4537.html 7/8/2004 - httpd Multiple vulnerabilities Updated httpd packages that fix a buffer overflow in mod_ssl and a remotely triggerable memory leak are now available. http://www.linuxsecurity.com/advisories/redhat_advisory-4538.html +---------------------------------+ | Distribution: Suse | ----------------------------// +---------------------------------+ 7/8/2004 - kernel Multiple vulnerabilities Multiple security vulnerabilities are being addressed with this security update of the Linux kernel. http://www.linuxsecurity.com/advisories/suse_advisory-4535.html ------------------------------------------------------------------------ Distributed by: Guardian Digital, Inc. 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