+---------------------------------------------------------------------+ | LinuxSecurity.com Weekly Newsletter | | July 16, 2004 Volume 5, Number 28a | +---------------------------------------------------------------------+ 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 kernel, Ethereal, MoinMoin and rsync. The distributors include EnGarde, Fedora, Gentoo and Mandrake. ----- >> 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 ----- How Does Kerberos Actually Work? Kerberos uses secret-key cryptography to distribute tickets used for authentication of users to network services. The ticket is generated using a password that the user supplies, unequivocally linking it to the user. The services available for use with Kerberos also have tickets, but are not generated using a password. The user presents his ticket given to him by the Kerberos authentication server. The ticket is stored on the authentication server, which is configured to permit the user to access a particular service on a particular server on the network. The server uses this to verify the user's identity, and grants or denies access to a particular network service. Once the user has requested of the AS the use of a particular service, a session key (a random string of bits) is generated which is used to encrypt future communications between the client and AS. This key and the service name requested are encrypted together using the user's ticket. Another copy of the random session key generated by the AS and the username are encrypted together using the service's key. Both keys are then returned to the user. The user decrypts the first message using his ticket and reveals the server name from which he was requesting service and the session key generated by the AS. The second message passed to the user cannot be decrypted because it was encrypted using the service key, which the user does not have. The user then uses that session key to encrypt a message containing the current time. This message, and the second message still encrypted, are both passed to the service for which the user requests access. The service opens the first message (the one the client could not open) using its own key, extracting the session key and the user name requesting the use of the service. The service then opens the second message using the session key from the previous message to extract the message with the timestamp on it. This then serves to authenticate the user. This message may also contain an encryption key that is used to provide privacy in future communications between the user and the service. Security Tip Written by Dave Wreski (dave@xxxxxxxxxxxxxxxxxxx) Additional tips are available at the following URL: http://www.linuxsecurity.com/tips/ ----- Catching up with Wietse Venema, creator of Postfix and TCP Wrapper Duane Dunston speaks at length with Wietse Venema on his current research projects at the Thomas J. Watson Research Center, including his forensics efforts with The Coroner's Toolkit. Wietse Venema is best known for the software TCP Wrapper, which is still widely used today and is included with almost all unix systems. Wietse is also the author of the Postfix mail system and the co-author of the very cool suite of utilities called The Coroner's Toolkit or "TCT". http://www.linuxsecurity.com/feature_stories/feature_story-169.html ------------------------------------------------------------------- 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 ------ --> Take advantage of the LinuxSecurity.com Quick Reference Card! --> http://www.linuxsecurity.com/docs/QuickRefCard.pdf +---------------------------------+ | Distribution: EnGarde | ----------------------------// +---------------------------------+ 7/13/2004 - kernel Multiple vulnerabilities This update fixes several security vulnerabilities in the Linux Kernel shipped with EnGarde Secure Linux, most notably the "fsave/frstor" vulnerability and an information leak in the e1000 driver. http://www.linuxsecurity.com/advisories/engarde_advisory-4555.html +---------------------------------+ | Distribution: Fedora | ----------------------------// +---------------------------------+ 7/9/2004 - im-sdk Insecure temporary file vulnerability Multiple vulnerabilities The im-switch that is included in the Fedora Core iiimf-x package has been fixed to take appropriate precautions when generating temporary files. http://www.linuxsecurity.com/advisories/fedora_advisory-4551.html +---------------------------------+ | Distribution: Gentoo | ----------------------------// +---------------------------------+ 7/9/2004 - Ethereal Multiple vulnerabilities Multiple vulnerabilities including one buffer overflow exist in Ethereal, which may allow an attacker to run arbitrary code or crash the program. http://www.linuxsecurity.com/advisories/gentoo_advisory-4550.html 7/12/2004 - MoinMoin ACL bypass vulnerability MoinMoin contains a bug allowing a user to bypass group ACLs (Access Control Lists). http://www.linuxsecurity.com/advisories/gentoo_advisory-4553.html 7/12/2004 - rsync Directory traversal vulnerability Under specific conditions, the rsync daemon is vulnerable to a directory traversal allowing to write files outside a sync module. http://www.linuxsecurity.com/advisories/gentoo_advisory-4554.html +---------------------------------+ | Distribution: Mandrake | ----------------------------// +---------------------------------+ 7/9/2004 - ethereal Multiple vulnerabilities It may be possible to make Ethereal crash or run arbitrary code by injecting a purposefully malformed packet into the wire or by convincing someone to read a malformed packet trace file. http://www.linuxsecurity.com/advisories/mandrake_advisory-4552.html ------------------------------------------------------------------------ Distributed by: Guardian Digital, Inc. LinuxSecurity.com To unsubscribe email vuln-newsletter-request@xxxxxxxxxxxxxxxxx with "unsubscribe" in the subject of the message. ------------------------------------------------------------------------
