Protect yourself against future threats.
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AUSCERT External Security Bulletin Redistribution
ESB-2020.2104
New BIND releases are available: 9.11.20, 9.16.4, and 9.17.2
18 June 2020
===========================================================================
AusCERT Security Bulletin Summary
---------------------------------
Product: BIND
Publisher: ISC
Operating System: UNIX variants (UNIX, Linux, OSX)
Windows
Impact/Access: Denial of Service -- Existing Account
Resolution: Patch/Upgrade
CVE Names: CVE-2020-8619 CVE-2020-8618
Original Bulletin:
https://lists.isc.org/pipermail/bind-announce/2020-June/001157.html
https://lists.isc.org/pipermail/bind-announce/2020-June/001158.html
https://lists.isc.org/pipermail/bind-announce/2020-June/001159.html
Comment: This bulletin contains two (2) ISC security advisories.
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CVE: CVE-2020-8618
Document version: 2.0
Posting date: 17 June 2020
Program impacted: BIND
Versions affected: BIND 9.16.0 -> 9.16.3
Severity: Medium
Exploitable:
Remotely
Description:
An assertion check in BIND (that is meant to prevent going beyond
the end of a buffer when processing incoming data) can be
incorrectly triggered by a large response during zone transfer.
Impact:
An attacker who is permitted to send zone data to a server via
zone transfer can exploit this to intentionally trigger the
assertion failure with a specially constructed zone, denying
service to clients.
CVSS Score: 4.3
CVSS Vector: AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H/E:U/RL:O/RC:C
For more information on the Common Vulnerability Scoring System and
to obtain your specific environmental score please visit:
https://nvd.nist.gov/vuln-metrics/cvss/v3-calculator?vector=AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H/E:U/RL:O/RC:C&version=3.1.
Workarounds:
None
Active exploits:
We are not aware of any active exploits.
Solution:
Upgrade to the patched release most closely related to your
current version of BIND:
- BIND 9.16.4
Document revision history:
1.0 Early Notification, 10 June 2020
1.1 Simplified "Exploitable" section, 17 June 2020
2.0 Public disclosure, 17 June 2020
Related documents:
See our BIND 9 Security Vulnerability Matrix for a complete
listing of security vulnerabilities and versions affected.
Do you still have questions? Questions regarding this advisory
should go to security-officer@isc.org. To report a new issue, please
encrypt your message using security-officer@isc.org's PGP key which
can be found here: https://www.isc.org/pgpkey/. If you are unable
to use encrypted email, you may also report new issues at:
https://www.isc.org/reportbug/.
Note:
ISC patches only currently supported versions. When possible we
indicate EOL versions affected. (For current information on which
versions are actively supported, please see
https://www.isc.org/download/.)
ISC Security Vulnerability Disclosure Policy:
Details of our current security advisory policy and practice can
be found in the ISC Software Defect and Security Vulnerability
Disclosure Policy at https://kb.isc.org/docs/aa-00861.
The Knowledgebase article https://kb.isc.org/docs/cve-2020-8618 is
the complete and official security advisory document.
Legal Disclaimer:
Internet Systems Consortium (ISC) is providing this notice on
an "AS IS" basis. No warranty or guarantee of any kind is expressed
in this notice and none should be implied. ISC expressly excludes
and disclaims any warranties regarding this notice or materials
referred to in this notice, including, without limitation, any
implied warranty of merchantability, fitness for a particular
purpose, absence of hidden defects, or of non-infringement. Your
use or reliance on this notice or materials referred to in this
notice is at your own risk. ISC may change this notice at any
time. A stand-alone copy or paraphrase of the text of this
document that omits the document URL is an uncontrolled copy.
Uncontrolled copies may lack important information, be out of
date, or contain factual errors.
_______________________________________________
bind-announce mailing list
bind-announce@lists.isc.org
https://lists.isc.org/mailman/listinfo/bind-announce
- --------------------------------------------------------------------------------
Note: this Security Advisory for BIND concerns a vulnerability which
can exist when a zone contains an empty non-terminal record whose label
contains an asterisk character ("*"). If you are not familiar with the
idea of "empty non-terminals", you might wish to read this article in
our Knowledge Base: https://kb.isc.org/docs/what-is-an-empty-non-terminal
- -----
CVE: CVE-2020-8619
Document version: 2.0
Posting date: 17 June 2020
Program impacted: BIND
Versions affected: BIND 9.11.14 -> 9.11.19, BIND 9.14.9 -> 9.14.12,
BIND 9.16.0 -> 9.16.3. Also, versions 9.11.14-S1 ->
9.11.19-S1 of BIND Supported Preview Edition
Severity: Medium
Exploitable:
Remotely, but only if records matching a certain pattern are
present in a zone being served.
Description:
The asterisk character ("*") is allowed in DNS zone files, where
it is most commonly present as a wildcard at a terminal node of
the Domain Name System graph. However, the RFCs do not require
and BIND does not enforce that an asterisk character be present
only at a terminal node.
A problem can occur when an asterisk is present in an empty
non-terminal location within the DNS graph. If such a node exists,
after a series of queries, named can reach an inconsistent state
that results in the failure of an assertion check in rbtdb.c,
followed by the program exiting due to the assertion failure.
Impact:
Unless a nameserver is providing authoritative service for one
or more zones and at least one zone contains an empty non-terminal
entry containing an asterisk ("*") character, this defect cannot
be encountered.
A would-be attacker who is allowed to change zone content could
theoretically introduce such a record in order to exploit this
condition to cause denial of service, though we consider the use
of this vector unlikely because any such attack would require a
significant privilege level and be easily traceable.
CVSS Score: 4.3
CVSS Vector: AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H/E:U/RL:O/RC:C
For more information on the Common Vulnerability Scoring System and
to obtain your specific environmental score please visit:
https://nvd.nist.gov/vuln-metrics/cvss/v3-calculator?vector=AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:U/RL:O/RC:C&version=3.1.
Workarounds:
None
Active exploits:
We are not aware of any active exploits.
Solution:
Upgrade to the patched release most closely related to your
current version of BIND:
- BIND 9.11.20
- BIND 9.16.4
BIND Supported Preview Edition is a special feature preview
branch of BIND provided to eligible ISC support customers.
- BIND 9.11.20-S1
Document revision history:
1.0 Early Notification, 10 June 2020
1.1 Corrected "Versions affected" to list Supported Preview
Edition releases, 17 June 2020
2.0 Public disclosure, 17 June 2020
Related documents:
See our BIND 9 Security Vulnerability Matrix for a complete
listing of security vulnerabilities and versions affected.
Do you still have questions? Questions regarding this advisory
should go to security-officer@isc.org. To report a new issue, please
encrypt your message using security-officer@isc.org's PGP key which
can be found here: https://www.isc.org/pgpkey/. If you are unable
to use encrypted email, you may also report new issues at:
https://www.isc.org/reportbug/.
Note:
ISC patches only currently supported versions. When possible we
indicate EOL versions affected. (For current information on which
versions are actively supported, please see https://www.isc.org/download/.)
ISC Security Vulnerability Disclosure Policy:
Details of our current security advisory policy and practice can
be found in the ISC Software Defect and Security Vulnerability
Disclosure Policy at https://kb.isc.org/docs/aa-00861.
The Knowledgebase article https://kb.isc.org/docs/cve-2020-8619 is
the complete and official security advisory document.
Legal Disclaimer:
Internet Systems Consortium (ISC) is providing this notice on
an "AS IS" basis. No warranty or guarantee of any kind is expressed
in this notice and none should be implied. ISC expressly excludes
and disclaims any warranties regarding this notice or materials
referred to in this notice, including, without limitation, any
implied warranty of merchantability, fitness for a particular
purpose, absence of hidden defects, or of non-infringement. Your
use or reliance on this notice or materials referred to in this
notice is at your own risk. ISC may change this notice at any
time. A stand-alone copy or paraphrase of the text of this
document that omits the document URL is an uncontrolled copy.
Uncontrolled copies may lack important information, be out of
date, or contain factual errors.
_______________________________________________
bind-announce mailing list
bind-announce@lists.isc.org
https://lists.isc.org/mailman/listinfo/bind-announce
- --------------------------END INCLUDED TEXT--------------------
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===========================================================================
Australian Computer Emergency Response Team
The University of Queensland
Brisbane
Qld 4072
Internet Email: auscert@auscert.org.au
Facsimile: (07) 3365 7031
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