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-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 =========================================================================== AUSCERT External Security Bulletin Redistribution ESB-2014.0841 Potential DOS in Samba internal DNS server 29 May 2014 =========================================================================== AusCERT Security Bulletin Summary --------------------------------- Product: Samba Publisher: The Samba Team Operating System: UNIX variants (UNIX, Linux, OSX) Impact/Access: Denial of Service -- Remote/Unauthenticated Resolution: Patch/Upgrade CVE Names: CVE-2014-0239 Original Bulletin: http://www.samba.org/samba/security/CVE-2014-0239 - --------------------------BEGIN INCLUDED TEXT-------------------- CVE-2014-0239.html: =========================================================== == Subject: Potential DOS in Samba internal DNS server == == CVE ID#: CVE-2014-0239 == == Versions: All versions of Samba later than 4.0.0 == == Summary: The internal DNS server does not check the "reply" flag, == potentially causing a packet loop. == =========================================================== =========== Description =========== Samba versions 4.0.0 and above have a flaw in DNS protocol handling in the internal DNS server. The server will not check the "reply" flag in the DNS packet header when processing a request. That makes it vulnerable to reply to a spoofed reply packet with another reply. Two affected servers could thus DOS each other. ================== Patch Availability ================== Patches addressing this issue have been posted to: http://www.samba.org/samba/security/ Samba version 4.0.18 includes a patch for this issue. ========== Workaround ========== Use the BIND_DLZ DNS backend to avoid this issue. ======= Credits ======= This problem was reported on IRC by a Samba user Patch provided by Kai Blin of the Samba team. ========================================================== == Our Code, Our Bugs, Our Responsibility. == The Samba Team ========================================================== - --------------------------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 =========================================================================== Australian Computer Emergency Response Team The University of Queensland Brisbane Qld 4072 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 iQIVAwUBU4a1chLndAQH1ShLAQISRw/8CZBaHkOSKQ/2WBq6n/TRNbd49LaEPfUK GgKJRpxKqThwORJ5LlGZbSEP73ZdSZV81C3CJ6Tlp6iCtEDR25IFHhbWkgVhVvzS QCjWunpeudm1XAMpoObN/x/5GY+9ga5JMiE1cjYBP6402t+ranpWaoufULWMIzGr kJxUAfYf4DWwKA/HjkTjjm6xCA1GBIAZOHqabYHKgPqPby3ykOmx9PyDOgYBQ2ei nAR7lfph7NQf7lMGoj3X0c0Gx66Y109JWYo6Xgez8xb5S9gVY3ij8q9gNN5TNyDS B1aAIWFjy0LCyWdzvqlrZQcEF92444gKpxVAlP8QjPk5BpDgsPAojYrF1MyjWHbQ qNt3MAtmBcI2YfgTvZrGUm+gF9r8NssJ7grNF61KvnJ3ogePyBhuwroVPb41fR3b HxKJZok01N9q42WQIFGTBaPucXb7EKcRzyN4ZDdOOJBuEyKeN5z4nAzc3/gEVFld XF2PX86AMoEG76x+aczqw11+BSKd2YAdhQTRk12SWPJLTygrtSRIG61R5NBd2LGv hPjRBxyqHhbjQkOYIpqqA4Q3inbXLnd2+HF/0g8mWDt7scI6rlbbs0YqpaKg42dL hEu7Kqdu2Z9i+r6FoLae6n3I7F1PK8pktygOF/kVWoQ1lccKocykPc+zGhvF4OzW 0g3Y3ihtk14= =hTTT -----END PGP SIGNATURE-----