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ESB-2014.0841 - [UNIX/Linux] Samba: Denial of service - Remote/unauthenticated

Date: 29 May 2014

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             AUSCERT External Security Bulletin Redistribution

                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:

- --------------------------BEGIN INCLUDED TEXT--------------------


== 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.


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:

Samba version 4.0.18 includes a patch for this issue.


Use the BIND_DLZ DNS backend to avoid this issue.


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--------------------

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