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-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 =========================================================================== AUSCERT External Security Bulletin Redistribution ESB-2004.0406 -- Sun Alert Notification - Sun Alert ID: 57580 Solaris/SEAM Kerberos 5 Vulnerability Due To Buffer Overflows In krb5_aname_to_localname() 15 June 2004 =========================================================================== AusCERT Security Bulletin Summary --------------------------------- Product: Kerberos 5 Publisher: Sun Microsystems Operating System: Solaris 8 Solaris 9 SEAM 1.0 (for Solaris 7) SEAM 1.0.1 (for Solaris 8) SEAM 1.0.2 (for Solaris 9) Impact: Root Compromise Access Required: Existing Account Ref: ESB-2004.0378 Comment: Original Bulletin: http://sunsolve.sun.com/pub-cgi/retrieve.pl?doc=fsalert%2F57580 - --------------------------BEGIN INCLUDED TEXT-------------------- DOCUMENT ID: 57580 SYNOPSIS: Solaris/SEAM Kerberos 5 Vulnerability Due To Buffer Overflows In krb5_aname_to_localname() DETAIL DESCRIPTION: Sun(sm) Alert Notification * Sun Alert ID: 57580 * Synopsis: Solaris/SEAM Kerberos 5 Vulnerability Due To Buffer Overflows In krb5_aname_to_localname() * Category: Security * Product: Solaris, Solaris Enterprise Authentication Mechanism (SEAM) * BugIDs: 5055875 * Avoidance: Workaround * State: Committed * Date Released: 10-Jun-2004 * Date Closed: * Date Modified: 1. Impact On Kerberos 5 enabled systems using auth_to_local mapping through appropriate entries in the krb5 configuration file krb5.conf(4); an unprivileged local or remote user with kerberos credentials may be able to execute arbitrary code with root privileges due to buffer overflows in krb5_aname_to_localname() function. This issue is described in CERT vulnerability VU#686862 at [1]http://www.kb.cert.org/vuls/id/686862 and MIT krb5 Security Advisory 2004-001 at [2]http://web.mit.edu/kerberos/advisories/MITKRB5-SA-2004-001-an_to_ln .txt. 2. Contributing Factors This issue can occur in the following releases: SPARC Platform * Solaris 8 * Solaris 9 * SEAM 1.0 (for Solaris 7) * SEAM 1.0.1 (for Solaris 8) * SEAM 1.0.2 (for Solaris 9) x86 Platform * Solaris 8 * Solaris 9 * SEAM 1.0 (for Solaris 7) * SEAM 1.0.1 (for Solaris 8) * SEAM 1.0.2 (for Solaris 9) Note: Solaris Enterprise Authentication Mechanism (SEAM) is an unbundled product available for Solaris 7, 8 and 9. For more information on SEAM, please see the SEAM(5) man page. For Solaris without SEAM, this issue may only occur if the system is configured to be a Kerberos client, verified by running the following command: % grep default_realm /etc/krb5/krb5.conf | grep -v __default_realm__default _realm = EXAMPLE.COM If the command returns no output or the krb5.conf(4) file is not found, then the system is not configured for Kerberos. In addition, systems are only vulnerable to this issue if they have been configured to enable the "explicit" mapping or "rules-based" mapping of the principal mapping functionality. This is not the default configuration. A system which is vulnerable will have one of the following entries in the krb5 configuration file (see krb5.conf(4)): The explicit mapping form is similar to: auth_to_local_names = { aname = lname } The rule-based mapping form is similar to: auth_to_local = RULE:foo 3. Symptoms There are no predictable symptoms that would indicate the described issue has been exploited. SOLUTION SUMMARY: 4. Relief/Workaround To work around the described issue, disable the "auth_to_local" rules by commenting out the code for "auth_to_local" from the "/etc/krb5/krb5.conf" configuration file. 5. Resolution A final resolution is pending completion. This Sun Alert notification is being provided to you on an "AS IS" basis. This Sun Alert notification may contain information provided by third parties. The issues described in this Sun Alert notification may or may not impact your system(s). Sun makes no representations, warranties, or guarantees as to the information contained herein. ANY AND ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, OR NON-INFRINGEMENT, ARE HEREBY DISCLAIMED. BY ACCESSING THIS DOCUMENT YOU ACKNOWLEDGE THAT SUN SHALL IN NO EVENT BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, PUNITIVE, OR CONSEQUENTIAL DAMAGES THAT ARISE OUT OF YOUR USE OR FAILURE TO USE THE INFORMATION CONTAINED HEREIN. This Sun Alert notification contains Sun proprietary and confidential information. It is being provided to you pursuant to the provisions of your agreement to purchase services from Sun, or, if you do not have such an agreement, the Sun.com Terms of Use. This Sun Alert notification may only be used for the purposes contemplated by these agreements. Copyright 2000-2004 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, CA 95054 U.S.A. All rights reserved. References 1. http://www.kb.cert.org/vuls/id/686862 2. http://web.mit.edu/kerberos/advisories/MITKRB5-SA-2004-001-an_to_ln.txt - --------------------------END INCLUDED TEXT-------------------- You have received this e-mail bulletin as a result of your organisation's registration with AusCERT. The mailing list you are subscribed to is maintained within your organisation, so if you do not wish to continue receiving these bulletins you should contact your local IT manager. If you do not know who that is, please send an email to auscert@auscert.org.au and we will forward your request to the appropriate person. NOTE: Third Party Rights This security bulletin is provided as a service to AusCERT's members. As AusCERT did not write the document quoted above, AusCERT has had no control over its content. The decision to follow or act on information or advice contained in this security bulletin is the responsibility of each user or organisation, and should be considered in accordance with your organisation's site policies and procedures. AusCERT takes no responsibility for consequences which may arise from following or acting on information or advice contained in this security bulletin. NOTE: This is only the original release of the security bulletin. It may not be updated when updates to the original are made. If downloading at a later date, it is recommended that the bulletin is retrieved directly from the author's website to ensure that the information is still current. Contact information for the authors of the original document is included in the Security Bulletin above. If you have any questions or need further information, please contact them directly. Previous advisories and external security bulletins can be retrieved from: http://www.auscert.org.au/render.html?cid=1980 If you believe that your computer system has been compromised or attacked in any way, we encourage you to let us know by completing the secure National IT Incident Reporting Form at: http://www.auscert.org.au/render.html?it=3192 Internet Email: auscert@auscert.org.au Facsimile: (07) 3365 7031 Telephone: (07) 3365 4417 (International: +61 7 3365 4417) AusCERT personnel answer during Queensland business hours which are GMT+10:00 (AEST). On call after hours for member emergencies only. -----BEGIN PGP SIGNATURE----- Comment: http://www.auscert.org.au/render.html?it=1967 iQCVAwUBQM5tsyh9+71yA2DNAQJSVQP+Lv2X8jzDPHLBuvTQiv29Ly0rduGt3WGb yPMAvwNXDFgxvHRIjuZcnAkqVSsrgnf/pCZ8SyvgUIuE5/r6UryQPxhuMtI6MTdp TV6+KycXyw0WvCCQZdQcaAmBu8uvuvppRElGuXBkB8gvXb52A4AfxLkpjcu5xfhU 6Y6ti5VK3Uw= =RdoW -----END PGP SIGNATURE-----