BIND: CVE-2019-6468: BIND Supported Preview Edition can exit with an assertion f

[icecream-guy]

CVE-2019-6468: BIND Supported Preview Edition can exit with an assertion failure if nxdomain-redirect is used

CVE:                 CVE-2019-6468
Document version:    2.0
Posting date:        24 April 2019
Program impacted:    BIND
Versions affected:   BIND Supported Preview Edition version
                     9.10.5-S1 -> 9.11.5-S5. ONLY BIND Supported
                     Preview Edition releases are affected.
Severity:            Medium
Exploitable:         Remotely

Description:

   In BIND Supported Preview Edition, an error in the nxdomain-redirect
   feature can occur in versions which support EDNS Client Subnet
   (ECS) features. In those versions which have ECS support, enabling
   nxdomain-redirect is likely to lead to BIND exiting due to
   assertion failure.

Impact:

   If nxdomain-redirect is enabled (via configuration) in a vulnerable
   BIND release, a malicious party can cause BIND to exit by
   deliberately triggering the bug.

CVSS Score:          5.9
CVSS Vector:         CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

For more information on the Common Vulnerability Scoring System and to obtain your specific environmental score please visit:
https://www.first.org/cvss/calculator/3.0#CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H.

Workarounds:

   Exploitation of this defect can be effectively prevented by
   disabling the nxdomain-redirect feature in the nameserver's
   configuration.

Active exploits:

   None known.

Solution:

   Upgrade to the patched release most closely related to your
   current version of BIND:

   BIND Supported Preview Edition is a special feature preview
   branch of BIND provided to eligible ISC support customers.

   -  BIND 9.11.5-S6
   -  BIND 9.11.6-S1

Document revision history:

   1.0 Early Notification, 15 April 2019
   1.1 Added reference to BIND 9.11.6-S1 in Solution section
   2.0 Public Disclosure, 24 April 2019

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/downloads/software-support-policy/openpgp-key
If you are unable to use encrypted email, you may also report new issues at: https://www.isc.org/community/report-bug/.

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/downloads/.)

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.

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