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                              CERT-Renater

                 Note d'Information No. 2017/VULN389
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DATE                : 11/12/2017

HARDWARE PLATFORM(S): /

OPERATING SYSTEM(S): Systems running PowerDNS versions 4.0.x prior to
                                         4.0.8.

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https://doc.powerdns.com/recursor/security-advisories/powerdns-advisory-2017-08.html
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PowerDNS Security Advisory 2017-08: Crafted CNAME answer can cause a
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denial of service
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-  CVE: CVE-2017-15120
-  Date: December 11th 2017
-  Credit: Toshifumi Sakaguchi
-  Affects: PowerDNS Recursor from 4.0.0 up to and including 4.0.7
-  Not affected: PowerDNS Recursor 3.7.4, 4.0.8, 4.1.0
-  Severity: High
-  Impact:  Denial of service
-  Exploit: This problem can be triggered by an authoritative server
   sending a crafted CNAME answer with a class other than IN to the
   Recursor.
-  Risk of system compromise: No
-  Solution: Upgrade to a non-affected version
-  Workaround: run the process inside a supervisor like supervisord or
   systemd

An issue has been found in the parsing of authoritative answers in
PowerDNS Recursor, leading to a NULL pointer dereference when parsing a
specially crafted answer containing a CNAME of a different class than
IN. This issue has been assigned CVE-2017-15120.

When the PowerDNS Recursor is run inside a supervisor like supervisord
or systemd, it will be automatically restarted, limiting the impact to
somewhat degraded service.

PowerDNS Recursor from 4.0.0 up to and including 4.0.7 are affected.

For those unable to upgrade to a new version, a minimal patch is
`available <https://downloads.powerdns.com/patches/2017-08>`__

We would like to thank Toshifumi Sakaguchi for finding and subsequently
reporting this issue.


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+ CERT-RENATER          | tel : 01-53-94-20-44           +
+ 23 - 25 Rue Daviel    | fax : 01-53-94-20-41           +
+ 75013 Paris           | email: cert@support.renater.fr +
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