CVE-2018-5738 Information

Description

Change 4777 (introduced in October 2017) introduced an unforeseen issue in releases which were issued after that date affecting which clients are permitted to make recursive queries to a BIND nameserver. The intended (and documented) behavior is that if an operator has not specified a value for the \allow-recursion\ setting it SHOULD default to one of the following: none if \recursion no;\ is set in named.conf; a value inherited from the \allow-query-cache\ or \allow-query\ settings IF \recursion yes;\ (the default for that setting) AND match lists are explicitly set for \allow-query-cache\ or \allow-query\ (see the BIND9 Administrative Reference Manual section 6.2 for more details); or the intended default of \allow-recursion localhost; localnets;;\ if \recursion yes;\ is in effect and no values are explicitly set for \allow-query-cache\ or \allow-query. However because of the regression introduced by change 4777 it is possible when \recursion yes;\ is in effect and no match list values are provided for \allow-query-cache\ or \allow-query\ for the setting of \allow-recursion\ to inherit a setting of all hosts from the \allow-query\ setting default improperly permitting recursion to all clients. Affects BIND 9.9.12 9.10.7 9.11.3 9.12.0-9.12.1-P2 the development release 9.13.0 and also releases 9.9.12-S1 9.10.7-S1 9.11.3-S1 and 9.11.3-S2 from BIND 9 Supported Preview Edition.

CVSS Vector

CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

Reference

http://www.securitytracker.com/id/1041115 https://kb.isc.org/docs/aa-01616 https://security.gentoo.org/glsa/201903-13 https://security.netapp.com/advisory/ntap-20190830-0002/ https://usn.ubuntu.com/3683-1/

Attack Complexity

LOW

Privileges Required

NONE

User Interaction Required

NONE

Scope

NONE

Confidentiality Impact

UNCHANGED

Integrity Impact

HIGH

Availability Impact

NONE

Base Score

NONE

Base Severity

7.5