CVE-2021-25214

A broken inbound incremental zone update (IXFR) can cause named to terminate unexpectedly

Description

In BIND 9.8.5 -> 9.8.8, 9.9.3 -> 9.11.29, 9.12.0 -> 9.16.13, and versions BIND 9.9.3-S1 -> 9.11.29-S1 and 9.16.8-S1 -> 9.16.13-S1 of BIND 9 Supported Preview Edition, as well as release versions 9.17.0 -> 9.17.11 of the BIND 9.17 development branch, when a vulnerable version of named receives a malformed IXFR triggering the flaw described above, the named process will terminate due to a failed assertion the next time the transferred secondary zone is refreshed.

Remediation

Solution:

  • Upgrade to the patched release most closely related to your current version of BIND: BIND 9.11.31 BIND 9.16.15 BIND 9.17.12 BIND Supported Preview Edition is a special feature preview branch of BIND provided to eligible ISC support customers. BIND 9.11.31-S1 BIND 9.16.15-S1

Workaround:

  • Disabling incremental zone transfers (IXFR) by setting request-ixfr no; in the desired configuration block (options, zone, or server) prevents the failing assertion from being evaluated.

Category

6.5
CVSS
Severity: Medium
CVSS 3.1 •
CVSS 2.0 •
EPSS 0.64%
Vendor Advisory debian.org Vendor Advisory fedoraproject.org Vendor Advisory fedoraproject.org Vendor Advisory isc.org
Affected: ISC BIND9
Published at:
Updated at:

References

Link Tags
https://kb.isc.org/v1/docs/cve-2021-25214 vendor advisory
http://www.openwall.com/lists/oss-security/2021/04/29/1 third party advisory mailing list
http://www.openwall.com/lists/oss-security/2021/04/29/2 third party advisory mailing list
http://www.openwall.com/lists/oss-security/2021/04/29/3 third party advisory mailing list
http://www.openwall.com/lists/oss-security/2021/04/29/4 third party advisory mailing list
https://www.debian.org/security/2021/dsa-4909 third party advisory vendor advisory
https://lists.debian.org/debian-lts-announce/2021/05/msg00001.html third party advisory mailing list
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/VEC2XG4Q2ODTN2C4CGXEIXU3EUTBMK7L/ vendor advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ZDSRPCJQ7MZC6CENH5PO3VQOFI7VSWBE/ vendor advisory
https://security.netapp.com/advisory/ntap-20210521-0006/ third party advisory
https://cert-portal.siemens.com/productcert/pdf/ssa-389290.pdf third party advisory patch

Frequently Asked Questions

What is the severity of CVE-2021-25214?
CVE-2021-25214 has been scored as a medium severity vulnerability.
How to fix CVE-2021-25214?
To fix CVE-2021-25214: Upgrade to the patched release most closely related to your current version of BIND: BIND 9.11.31 BIND 9.16.15 BIND 9.17.12 BIND Supported Preview Edition is a special feature preview branch of BIND provided to eligible ISC support customers. BIND 9.11.31-S1 BIND 9.16.15-S1
Is CVE-2021-25214 being actively exploited in the wild?
As for now, there are no information to confirm that CVE-2021-25214 is being actively exploited. According to its EPSS score, there is a ~1% probability that this vulnerability will be exploited by malicious actors in the next 30 days.
What software or system is affected by CVE-2021-25214?
CVE-2021-25214 affects ISC BIND9.
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