CVE-2018-5740

A flaw in the "deny-answer-aliases" feature can cause an assertion failure in named

Description

"deny-answer-aliases" is a little-used feature intended to help recursive server operators protect end users against DNS rebinding attacks, a potential method of circumventing the security model used by client browsers. However, a defect in this feature makes it easy, when the feature is in use, to experience an assertion failure in name.c. Affects BIND 9.7.0->9.8.8, 9.9.0->9.9.13, 9.10.0->9.10.8, 9.11.0->9.11.4, 9.12.0->9.12.2, 9.13.0->9.13.2.

Remediation

Solution:

  • Most operators will not need to make any changes unless they are using the "deny-answer-aliases" feature (which is described in the BIND 9 Adminstrator Reference Manual section 6.2.) "deny-answer-aliases" is off by default; only configurations which explicitly enable it can be affected by this defect. If you are using "deny-answer-aliases", upgrade to the patched release most closely related to your current version of BIND. 9.9.13-P1 9.10.8-P1 9.11.4-P1 9.12.2-P1 BIND Supported Preview Edition is a special feature preview branch of BIND provided to eligible ISC support customers. 9.11.3-S3

Workaround:

  • This vulnerability can be avoided by disabling the "deny-answer-aliases" feature if it is in use.

Category

7.5
CVSS
Severity: High
CVSS 3.1 •
CVSS 3.0 •
CVSS 2.0 •
EPSS 66.03% Top 5%
Vendor Advisory redhat.com Vendor Advisory redhat.com Vendor Advisory ubuntu.com Vendor Advisory ubuntu.com Vendor Advisory gentoo.org Vendor Advisory opensuse.org Vendor Advisory opensuse.org Vendor Advisory isc.org
Affected: ISC BIND 9
Published at:
Updated at:

References

Link Tags
http://www.securityfocus.com/bid/105055 vdb entry third party advisory
https://lists.debian.org/debian-lts-announce/2018/08/msg00033.html third party advisory mailing list
https://access.redhat.com/errata/RHSA-2018:2570 third party advisory vendor advisory
https://access.redhat.com/errata/RHSA-2018:2571 third party advisory vendor advisory
https://usn.ubuntu.com/3769-2/ third party advisory vendor advisory
http://www.securitytracker.com/id/1041436 vdb entry third party advisory
https://security.netapp.com/advisory/ntap-20180926-0003/ third party advisory
https://kb.isc.org/docs/aa-01639 vendor advisory
https://usn.ubuntu.com/3769-1/ third party advisory vendor advisory
https://security.gentoo.org/glsa/201903-13 third party advisory vendor advisory
http://lists.opensuse.org/opensuse-security-announce/2019-06/msg00027.html mailing list third party advisory vendor advisory
http://lists.opensuse.org/opensuse-security-announce/2019-06/msg00026.html mailing list third party advisory vendor advisory
https://support.hpe.com/hpsc/doc/public/display?docLocale=en_US&docId=emr_na-hpesbux03927en_us third party advisory
https://lists.debian.org/debian-lts-announce/2021/11/msg00001.html third party advisory mailing list

Frequently Asked Questions

What is the severity of CVE-2018-5740?
CVE-2018-5740 has been scored as a high severity vulnerability.
How to fix CVE-2018-5740?
To fix CVE-2018-5740: Most operators will not need to make any changes unless they are using the "deny-answer-aliases" feature (which is described in the BIND 9 Adminstrator Reference Manual section 6.2.) "deny-answer-aliases" is off by default; only configurations which explicitly enable it can be affected by this defect. If you are using "deny-answer-aliases", upgrade to the patched release most closely related to your current version of BIND. 9.9.13-P1 9.10.8-P1 9.11.4-P1 9.12.2-P1 BIND Supported Preview Edition is a special feature preview branch of BIND provided to eligible ISC support customers. 9.11.3-S3
Is CVE-2018-5740 being actively exploited in the wild?
It is possible that CVE-2018-5740 is being exploited or will be exploited in a near future based on public information. According to its EPSS score, there is a ~66% probability that this vulnerability will be exploited by malicious actors in the next 30 days.
What software or system is affected by CVE-2018-5740?
CVE-2018-5740 affects ISC BIND 9.
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