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Re: CVE Request -- bind-dyndb-ldap: Bind DoS (named hang) by processing DNS query for zone served by bind-dyndb-ldap


From: Kurt Seifried <kseifried () redhat com>
Date: Tue, 24 Apr 2012 12:08:17 -0600

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On 04/24/2012 10:47 AM, Jan Lieskovsky wrote:
Note: First time mangled email address of Petr Spacek => apologize
if you got this email two times. Anyway:

Hello Kurt, Steve, vendors,

a denial of service flaw was found in the way the bind-dyndb-ldap,
a dynamic LDAP back-end plug-in for BIND providing LDAP database
back-end capabilities, performed LDAP connection errors handling /
attempted to recover, when an error during a LDAP search happened
for a particular DNS query. When the Berkeley Internet Name Domain
(BIND) server was patched to support dynamic loading of database
back-ends, and the LDAP database back-end was enabled, a remote 
attacker could use this flaw to cause denial of service (named
process hang) via DNS query for zone served by bind-dyndb-ldap.

bind-dyndb-ldap backend upstream commit, which introduced the
problem: [1] 
http://git.fedorahosted.org/git/?p=bind-dyndb-ldap.git;a=commit;h=a7a47212beb01c5083768bdd4170250e7f7cf188



Preliminary bind-dyndb-ldap back-end upstream patch from Adam
Tkac: [2] https://bugzilla.redhat.com/show_bug.cgi?id=815846#c1

References: [3] https://bugzilla.redhat.com/show_bug.cgi?id=815846 
[4]
https://www.redhat.com/archives/freeipa-users/2012-April/msg00145.html

 Note: Just to explicitly note this. This is NOT a bind DoS in the
sense upstream bind source package would be affected by it. Bind 
needs to be first patched to support dynamic loading of database 
backends and it's an error in the LDAP backend (bind-dyndb-ldap 
source code) which makes this attack to succeed when a 
specially-crafted DNS query is issued.

Could you allocate a CVE id for this?

Thank you && Regards, Jan. -- Jan iankko Lieskovsky / Red Hat
Security Response Team

Please use CVE-2012-2134 for this issue.

- -- 
Kurt Seifried Red Hat Security Response Team (SRT)
PGP: 0x5E267993 A90B F995 7350 148F 66BF 7554 160D 4553 5E26 7993

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