CVE-2021-25214

2021-04-2903:48:29

redhat.com

access.redhat.com

cve-2021-25214

incremental zone transfers

soa records

assertion failure

CVSS2

Attack Vector

NETWORK

Attack Complexity

LOW

Authentication

SINGLE

Confidentiality Impact

NONE

Integrity Impact

NONE

Availability Impact

PARTIAL

AV:N/AC:L/Au:S/C:N/I:N/A:P

CVSS3

6.5

Attack Vector

NETWORK

Attack Complexity

LOW

Privileges Required

LOW

User Interaction

NONE

Scope

UNCHANGED

Confidentiality Impact

NONE

Integrity Impact

NONE

Availability Impact

HIGH

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

EPSS

0.009

Percentile

83.0%

JSON

Incremental zone transfers (IXFR) provide a way of transferring changed portion(s) of a zone between servers. An IXFR stream containing SOA records with an owner name other than the transferred zone’s apex may cause the receiving named server to inadvertently remove the SOA record for the zone in question from the zone database. This leads to an assertion failure when the next SOA refresh query for that zone is made.

Mitigation

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.