CVE-2017-3145: Improper fetch cleanup sequencing in the resolver can cause named to crash
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
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.
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
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.
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 https://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
See our BIND 9 Security Vulnerability Matrix for a complete listing of Security Vulnerabilities and versions affected.
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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 https://www.isc.org/downloads/).
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