CVE-2020-8618: A buffer boundary check assertion in rdataset.c can fail incorrectly during zone transfer

Michael McNally mcnally at isc.org
Wed Jun 17 19:10:14 UTC 2020


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 at isc.org. To report a new issue, please
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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.

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