[lacnog] New vulnerability in ISC BIND can cause named to crash

[Lucimara Desiderá]

https://kb.isc.org/article/AA-01542


CVE-2017-3145: Improper fetch cleanup sequencing in the resolver can
cause named to crash

Author: ISC Support Reference Number: AA-01542 Views: 6251 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.

CVE: 		   CVE-2017-3145
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/.

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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 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.

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