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-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA256 =========================================================================== 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. - --------------------------BEGIN INCLUDED TEXT-------------------- 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-------------------- 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. 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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 iQIVAwUBWX6Q0Yx+lLeg9Ub1AQiTwg//QeIFcnNOvv+2eNxUxN8zJ6ln/GqA1eHN mpELUuohOKfVjUrAIyRl8dwzVzPjLc1XEknyCmKHHf+SaTh+PlnGwP8UraQ6D3a2 83q9f8Z4mzpKj4TEeAJNaHEye5XBa3+z87g/9sbqYvAZp5RDTNd8pwjc3N62wtAc 7I2TMLmqxBjhvq1M3wS5RtDopFDLurlPCtXC1nB3l4tp+ELioo7w003aEmYoWZ3D Jn9f2xgbDI/sAgL9bYK3bpCd0hZLnDm5gWfAkI4oywiZUu9zXWycWvSRHKeOXja/ UxtWcvlMY98m+wohwx5FSLbHl33rsMH+wAiBWcYaTe4zb0OB89u0d046va7cRneX mgPAU6+VXOQolusPUCtNBygVhqq3JoLT/vtdhLQtX5aaA+3x0HpPsm+ZhV6HA1Dh dYqA2IBKMVUOnnE3jnESysh0GKgHimXew9jt29dI7jp/I3i3J5ONXZ0N1oNYiDF2 GxK0FuJ0S4HOI0k8UdE9aDnz8D1MiJw7zgLdq+9BzgNZNn5OUEpsx0oGN+xAohjC NCqGDC6GjyDJqpFAPe6l/sWk+St94fg5B+m77mayB5sjU5U/+GCb2wGLbXiLuru9 UfD3slOythE5Sbo20SxOHQjU+x0jNY8Jkjj4GBzSVB9/y51DmncsRbRHmRC2BUTw Eh3w+PRi6Ts= =iXev -----END PGP SIGNATURE-----