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AUSCERT External Security Bulletin Redistribution
ESB-2017.1859
Multiple vulnerabilities have been identified in BIND
31 July 2017
===========================================================================
AusCERT Security Bulletin Summary
---------------------------------
Product: BIND
Publisher: ISC
Operating System: Windows
UNIX variants (UNIX, Linux, OSX)
Impact/Access: Provide Misleading Information -- Remote/Unauthenticated
Access Confidential Data -- Remote/Unauthenticated
Resolution: Patch/Upgrade
CVE Names: CVE-2017-3143 CVE-2017-3142
Reference: ESB-2017.1713.2
ESB-2017.1689
ESB-2017.1640
ESB-2017.1638
Original Bulletin:
https://kb.isc.org/article/AA-01504
https://kb.isc.org/article/AA-01503
Comment: This bulletin contains two (2) ISC security advisories.
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CVE-2017-3142: An error in TSIG authentication can permit unauthorized
zone transfers
Author: Michael McNally
Reference Number: AA-01504
Created: 2017-06-29 19:30
Last Updated: 2017-06-29 20:31
An attacker may be able to circumvent TSIG authentication of AXFR and
NOTIFY requests.
CVE:
CVE-2017-3142
Document Version:
2.0
Posting date:
29 June 2017
Program Impacted:
BIND
Versions affected:
9.4.0->9.8.8, 9.9.0->9.9.10-P1, 9.10.0->9.10.5-P1, 9.11.0->9.11.1-P1,
9.9.3-S1->9.9.10-S2, 9.10.5-S1->9.10.5-S2
Severity:
Medium
Exploitable:
Remotely
Description:
An attacker who is able to send and receive messages to an authoritative
DNS server and who has knowledge of a valid TSIG key name may be able to
circumvent TSIG authentication of AXFR requests via a carefully constructed
request packet. A server that relies solely on TSIG keys for protection
with no other ACL protection could be manipulated into:
providing an AXFR of a zone to an unauthorized recipient
accepting bogus NOTIFY packets
Impact:
An unauthorized AXFR (full zone transfer) permits an attacker to view
the entire contents of a zone. Protection of zone contents is often
a commercial or business requirement.
If accepted, a NOTIFY sets the zone refresh interval to 'now'. If there
is not already a refresh cycle in progress then named will initiate
one by asking for the SOA RR from its list of masters. If there
is already a refresh cycle in progress, then named will queue the
new refresh request. If there is already a queued refresh request,
the new NOTIFY will be discarded. Bogus notifications can't be used
to force a zone transfer from a malicious server, but could trigger
a high rate of zone refresh cycles.
CVSS Score: 5.3
CVSS Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
For more information on the Common Vulnerability Scoring System
and to obtain your specific environmental score please visit:
https://www.first.org/cvss/calculator/3.0#CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
Workarounds:
The effects of this vulnerability can be mitigated by using Access
Control Lists (ACLs) that require both address range validation
and use of TSIG authentication in conjunction. For information on
how to configure this type of compound authentication control, please see:
https://kb.isc.org/article/AA-00723/0/Using-Access-Control-Lists-ACLs-with-both-addresses-and-keys.html.
(Note that this technique may not be effective against bogus NOTIFY packets
if an attacker is able to reach the target DNS server whilst using a
spoofed sending address).
Active exploits:
No known active exploits but a similar issue was announced publicly on 23
June 2017 by another DNS server software provider.
Solution: Upgrade to the patched release most closely related
to your current version of BIND. These can all be downloaded from
http://www.isc.org/downloads.
BIND 9 version 9.9.10-P2
BIND 9 version 9.10.5-P2
BIND 9 version 9.11.1-P2
BIND Supported Preview Edition is a special feature preview branch of BIND
provided to eligible ISC support customers.
BIND 9 version 9.9.10-S3
BIND 9 version 9.10.5-S3
Acknowledgements: ISC would like to thank Clement Berthaux from Synacktiv
for reporting this issue.
Document Revision History:
1.0 Advance Notification 26 June 2017
1.1 Correct Notify to NOTIFY; Update phrasing in Workarounds section;
Update phrasing in Description; Correct date of similar public announcement,
29 June 2017
2.0 Public disclosure 29 June 2017
Related Documents:
See our BIND9 Security Vulnerability Matrix at
https://kb.isc.org/article/AA-00913 for a complete listing of Security
Vulnerabilities and versions affected.
If you'd like more information on ISC Subscription Support and Advance
Security Notifications, please visit http://www.isc.org/support/.
Do you still have questions? Questions regarding this advisory should
go to security-officer@isc.org. To report a new issue, please encrypt
your message using security-officer@isc.org's PGP key which can be found
here: https://www.isc.org/downloads/software-support-policy/openpgp-key/.
If you are unable to use encrypted email, you may also report new issues
at: https://www.isc.org/community/report-bug/.
Note: ISC patches only currently supported versions. When possible we
indicate EOL versions affected. (For current information on which versions
are actively supported, please see http://www.isc.org/downloads/).
ISC Security Vulnerability Disclosure Policy: Details of our
current security advisory policy and practice can be found here:
https://kb.isc.org/article/AA-00861/164/ISC-Software-Defect-and-Security-Vulnerability-Disclosure-Policy.html
This Knowledge Base article https://kb.isc.org/article/AA-01504 is the
complete and official security advisory document.
Legal Disclaimer:
Internet Systems Consortium (ISC) is providing this notice on an "AS IS"
basis. No warranty or guarantee of any kind is expressed in this notice and
none should be implied. ISC expressly excludes and disclaims any warranties
regarding this notice or materials referred to in this notice, including,
without limitation, any implied warranty of merchantability, fitness for a
particular purpose, absence of hidden defects, or of non-infringement. Your
use or reliance on this notice or materials referred to in this notice is at
your own risk. ISC may change this notice at any time. A stand-alone copy
or paraphrase of the text of this document that omits the document URL is
an uncontrolled copy. Uncontrolled copies may lack important information,
be out of date, or contain factual errors.
(C) 2001-2017 Internet Systems Consortium
For assistance with problems and questions for which you have not been able
to find an answer in our Knowledge Base, we recommend searching our community
mailing list archives and/or posting your question there (you will need
to register there first for your posts to be accepted). The bind-users and
the dhcp-users lists particularly have a long-standing and active membership.
ISC relies on the financial support of the community to fund the development
of its open source software products. If you would like to support future
product evolution and maintenance as well having peace of mind knowing that
our team of experts are poised to provide you with individual technical
assistance whenever you call upon them, then please consider our Professional
Subscription Support services - details can be found on our main website.
- ---------------------------------------------------------------------------
CVE-2017-3143: An error in TSIG authentication can permit unauthorized
dynamic updates
Author: Michael McNally
Reference Number: AA-01503
Created: 2017-06-29 19:30
Last Updated: 2017-07-06 21:07
An attacker may be able to forge a valid TSIG or signature for a dynamic
update.
CVE:
CVE-2017-3143
Document Version:
2.0
Posting date:
29 June 2017
Program Impacted:
BIND
Versions affected:
9.4.0->9.8.8, 9.9.0->9.9.10-P1, 9.10.0->9.10.5-P1, 9.11.0->9.11.1-P1,
9.9.3-S1->9.9.10-S2, 9.10.5-S1->9.10.5-S2
Severity:
High
Exploitable:
Remotely
Description:
An attacker who is able to send and receive messages to an authoritative
DNS server and who has knowledge of a valid TSIG key name for the zone
and service being targeted may be able to manipulate BIND into accepting
an unauthorized dynamic update.
Impact:
A server that relies solely on TSIG keys with no other address-based ACL
protection could be vulnerable to malicious zone content manipulation
using this technique.
Note that the local update policy (configured with "update-policy local;"
in named.conf) implicitly defines a key with a known key name (local-ddns)
and default algorithm and no IP-based access controls on the zone updates.
In conjunction with this failure in TSIG verification, "update-policy local"
is potentially very dangerous.
CVSS Score: 7.5
CVSS Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
For more information on the Common Vulnerability Scoring System
and to obtain your specific environmental score please visit:
https://www.first.org/cvss/calculator/3.0#CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
Workarounds:
The effects of this vulnerability can be mitigated by using Access
Control Lists (ACLs) that require both address range validation and
use of TSIG authentication in conjunction. For information on how to
configure this type of compound authentication control, please see:
https://kb.isc.org/article/AA-00723/0/Using-Access-Control-Lists-ACLs-with-both-addresses-and-keys.html.
Administrators who have made use of named.conf option "update-policy
local;" should patch their servers as soon as possible and if this is not
possible should replace the update-policy configuration statement with an
allow-update statement implementing the key requirement for updates but
additionally imposing an IP ACL limitation, e.g.:
allow-update { !{ !localhost; }; key local-ddns; };
Active exploits:
No known active exploits but a similar issue was announced publicly on 23
June 2017 by another DNS server software provider.
Solution: Upgrade to the patched release most closely related
to your current version of BIND. These can all be downloaded from
http://www.isc.org/downloads.
BIND 9 version 9.9.10-P2
BIND 9 version 9.10.5-P2
BIND 9 version 9.11.1-P2
BIND Supported Preview Edition is a special feature preview branch of BIND
provided to eligible ISC support customers.
BIND 9 version 9.9.10-S3
BIND 9 version 9.10.5-S3
Acknowledgements: ISC would like to thank Clement Berthaux from Synacktiv
for reporting this issue.
Document Revision History:
1.0 Advance Notification, 26 June 2017
1.1 CVSS score corrected (was previously erroneously listed as 7.8) 27
June 2017
1.2 Update phrasing in the Workarounds section; Correct date of similar
public announcement, 29 June 2017
1.3 Remove references to SIG(0), which is not affected, 29 June 2017
2.0 Public disclosure, 29 June 2017
2.1 "Impact" and "Workarounds" updated to better explain "update-policy
local;" risk, 6 July 2017
Related Documents:
See our BIND9 Security Vulnerability Matrix at
https://kb.isc.org/article/AA-00913 for a complete listing of Security
Vulnerabilities and versions affected.
If you'd like more information on ISC Subscription Support and Advance
Security Notifications, please visit http://www.isc.org/support/.
Do you still have questions? Questions regarding this advisory should
go to security-officer@isc.org. To report a new issue, please encrypt
your message using security-officer@isc.org's PGP key which can be found
here: https://www.isc.org/downloads/software-support-policy/openpgp-key/.
If you are unable to use encrypted email, you may also report new issues
at: https://www.isc.org/community/report-bug/.
Note: ISC patches only currently supported versions. When possible we
indicate EOL versions affected. (For current information on which versions
are actively supported, please see http://www.isc.org/downloads/).
ISC Security Vulnerability Disclosure Policy: Details of our
current security advisory policy and practice can be found here:
https://kb.isc.org/article/AA-00861/164/ISC-Software-Defect-and-Security-Vulnerability-Disclosure-Policy.html
This Knowledge Base article https://kb.isc.org/article/AA-01503 is the
complete and official security advisory document.
Legal Disclaimer:
Internet Systems Consortium (ISC) is providing this notice on an "AS IS"
basis. No warranty or guarantee of any kind is expressed in this notice and
none should be implied. ISC expressly excludes and disclaims any warranties
regarding this notice or materials referred to in this notice, including,
without limitation, any implied warranty of merchantability, fitness for a
particular purpose, absence of hidden defects, or of non-infringement. Your
use or reliance on this notice or materials referred to in this notice is at
your own risk. ISC may change this notice at any time. A stand-alone copy
or paraphrase of the text of this document that omits the document URL is
an uncontrolled copy. Uncontrolled copies may lack important information,
be out of date, or contain factual errors.
(C) 2001-2017 Internet Systems Consortium
For assistance with problems and questions for which you have not been able
to find an answer in our Knowledge Base, we recommend searching our community
mailing list archives and/or posting your question there (you will need
to register there first for your posts to be accepted). The bind-users and
the dhcp-users lists particularly have a long-standing and active membership.
ISC relies on the financial support of the community to fund the development
of its open source software products. If you would like to support future
product evolution and maintenance as well having peace of mind knowing that
our team of experts are poised to provide you with individual technical
assistance whenever you call upon them, then please consider our Professional
Subscription Support services - details can be found on our main website.
- --------------------------END INCLUDED TEXT--------------------
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