Bug 1869480 (CVE-2020-8624)

Summary: CVE-2020-8624 bind: incorrect enforcement of update-policy rules of type "subdomain"
Product: [Other] Security Response Reporter: Huzaifa S. Sidhpurwala <huzaifas>
Component: vulnerabilityAssignee: Red Hat Product Security <security-response-team>
Status: CLOSED ERRATA QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: aegorenk, anon.amish, mruprich, msehnout, pemensik, pzhukov, security-response-team, thozza, vonsch, yozone, zdohnal
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
Whiteboard:
Fixed In Version: bind 9.11.22, bind 9.16.6, bind 9.17.4 Doc Type: If docs needed, set a value
Doc Text:
A flaw was found in bind. Updates to "Update-policy" rules of type "subdomain" are treated as if they were of type "zonesub" which allows updates to all parts of the zone along with the intended subdomain. The highest threat from this vulnerability is to data integrity.
 Story Points: ---
Clone Of: Environment:
Last Closed: 2020-11-04 02:26:30 UTC Type: ---
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:
Bug Depends On: 1869501, 1869502, 1870906, 1874953, 1874955, 1874958, 1874961    
Bug Blocks: 1869469    
Attachments:
Description Flags
Patch against 9.11.22 none

Description Huzaifa S. Sidhpurwala 2020-08-18 05:10:33 UTC 
As per upstream advisory:

Change 4885 inadvertently caused "update-policy" rules of type "subdomain" to be treated as if they were of type "zonesub", allowing updates to all parts of the zone along with the intended subdomain.

An attacker who has been granted privileges to change a specific subset of the zone's content could abuse these unintended additional privileges to update other contents of the zone.
Comment 1 Huzaifa S. Sidhpurwala 2020-08-18 05:10:38 UTC 
Acknowledgments:

Name: ISC
Upstream: Joop Boonen (credativ GmbH)
Comment 2 Huzaifa S. Sidhpurwala 2020-08-18 06:50:46 UTC 
Created attachment 1711688 [details]
Patch against 9.11.22
Comment 4 Huzaifa S. Sidhpurwala 2020-08-21 02:20:26 UTC 
External References:

https://kb.isc.org/docs/cve-2020-8624
Comment 5 Huzaifa S. Sidhpurwala 2020-08-21 02:21:47 UTC 
Created bind tracking bugs for this issue:

Affects: fedora-all [bug 1870906]
Comment 6 Huzaifa S. Sidhpurwala 2020-08-26 16:05:16 UTC 
Upstream commit: https://gitlab.isc.org/isc-projects/bind9/-/commit/e4cccf9668c7adee4724a7649ec64685f82c8677
Comment 8 Petr Menšík 2020-09-03 16:51:53 UTC 
This error was introduced by upstream change 8f1ed05dc0a[1], which is contained only in 9.11 branch. Previous release 9.9.4 already has correct difference between "zonesub" and "subdomain" types. This is kind of regression noted much later.

1. https://gitlab.isc.org/isc-projects/bind9/commit/8f1ed05dc0aae7ae6c3da6ec6d405df61257a61e
Comment 18 errata-xmlrpc 2020-11-04 01:31:25 UTC 
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 8

Via RHSA-2020:4500 https://access.redhat.com/errata/RHSA-2020:4500
Comment 19 Product Security DevOps Team 2020-11-04 02:26:30 UTC 
This bug is now closed. Further updates for individual products will be reflected on the CVE page(s):

https://access.redhat.com/security/cve/cve-2020-8624
Comment 21 errata-xmlrpc 2020-11-10 13:00:05 UTC 
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 7

Via RHSA-2020:5011 https://access.redhat.com/errata/RHSA-2020:5011
Comment 23 errata-xmlrpc 2020-11-24 10:55:00 UTC 
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 7.7 Extended Update Support

Via RHSA-2020:5203 https://access.redhat.com/errata/RHSA-2020:5203