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CVE-2017-3145: Improper fetch cleanup sequencing in the resolver can cause named to crash
Author: ISC Support Reference Number: AA-01542 Views: 60246 Created: 2018-01-16 14:25 Last Updated: 2018-01-16 20:24 0 Rating/ Voters

Improper sequencing during cleanup can lead to a use-after-free error, triggering an assertion failure and crash in named.

Document Version: 
2.0
Posting date: 
16 January 2018
Program Impacted: 
BIND
Versions affected: 
9.0.0 to 9.8.x, 9.9.0 to 9.9.11, 9.10.0 to 9.10.6, 9.11.0 to 9.11.2, 9.9.3-S1 to 9.9.11-S1, 9.10.5-S1 to 9.10.6-S1, 9.12.0a1 to 9.12.0rc1
Severity: 
High
Exploitable: 
Remotely

Description:

BIND was improperly sequencing cleanup operations on upstream recursion fetch contexts, leading in some cases to a use-after-free error that can trigger an assertion failure and crash in named.

Impact:

While this bug has existed in BIND since 9.0.0, there are no known code paths leading to it in ISC releases prior to those containing the fix for CVE-2017-3137.  Thus while all instances of BIND ought to be patched, only ISC versions [9.9.9-P8 to 9.9.11, 9.10.4-P8 to 9.10.6, 9.11.0-P5 to 9.11.2, 9.9.9-S10 to 9.9.11-S1, 9.10.5-S1 to 9.10.6-S1, and 9.12.0a1 to 9.12.0rc1] acting as DNSSEC validating resolvers are currently known to crash due to this bug.  The known crash is an assertion failure in netaddr.c.

CVSS Score:  7.5

CVSS Vector:  CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

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:N/A:H

Workarounds:

If an operator is experiencing crashes due to this, temporarily disabling DNSSEC validation can be used to avoid the known problematic code path while replacement builds are prepared.

Active exploits:

No known active exploits but crashes due to this bug have been reported by multiple parties.

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 9.9.11-P1
  • BIND 9 version 9.10.6-P1
  • BIND 9 version 9.11.2-P1
  • BIND 9 version 9.12.0rc2

BIND Supported Preview Edition is a special feature preview branch of BIND provided to eligible ISC support customers.

  • BIND 9 version 9.9.11-S2
  • BIND 9 version 9.10.6-S2

Acknowledgements: ISC would like to thank Jayachandran Palanisamy of Cygate AB for making us aware of this vulnerability.

Document Revision History:

1.0 Advance Notification, 09 January 2018
1.1 Packager Notification, added acknowledgement,  15 January 2018
2.0 Public Release, 16 January 2018

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.orgTo 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-01542 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.



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