CVE-2018-5738
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…
Does this matter?
EPSS puts the probability of exploitation in the next 30 days at 11.2%, higher than 96% of all known CVEs. Patch or mitigate before the next change window.
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 3.0
- 7.5 HIGHCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
- EPSS
- 11.16% probability · 96th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-200
- Affected
- isc/bind · canonical/ubuntu linux
- Source
- security-officer@isc.org
References
- http://www.securitytracker.com/id/1041115Third Party Advisory, VDB Entry
- https://kb.isc.org/docs/aa-01616Mitigation, Vendor Advisory
- https://security.gentoo.org/glsa/201903-13Third Party Advisory
- https://security.netapp.com/advisory/ntap-20190830-0002/
- https://usn.ubuntu.com/3683-1/Third Party Advisory
- http://www.securitytracker.com/id/1041115Third Party Advisory, VDB Entry
- https://kb.isc.org/docs/aa-01616Mitigation, Vendor Advisory
- https://security.gentoo.org/glsa/201903-13Third Party Advisory
- https://security.netapp.com/advisory/ntap-20190830-0002/
- https://usn.ubuntu.com/3683-1/Third Party Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.