CVE-2020-8620: A specially crafted large TCP payload can trigger an assertion failure in tcpdns.c
Michael McNally
mcnally at isc.org
Thu Aug 20 18:48:12 UTC 2020
CVE: CVE-2020-8620
Document version: 2.0
Posting date: 20 August 2020
Program impacted: BIND
Versions affected: BIND 9.15.6 -> 9.16.5, 9.17.0 -> 9.17.3
Severity: Medium
Exploitable: Remotely
Description:
In versions of BIND that use the libuv network manager (9.16.x is the only
stable branch affected) an incorrectly specified maximum buffer size allows
a specially crafted large TCP payload to trigger an assertion failure when
it is received.
Impact:
An attacker who can establish a TCP connection with the server and send data
on that connection can exploit this to trigger the assertion failure,
causing the server to exit.
CVSS Score: 6.7
CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:P/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:P/RL:O/RC:C&version=3.1.
Workarounds:
No workarounds known.
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 9.16.6
- BIND 9.17.4
Acknowledgments:
ISC would like to thank Emanuel Almeida of Cisco Systems, Inc. for bringing
this vulnerability to our attention.
Document revision history:
1.0 Early Notification, 12 August 2020
1.1 Updated Posting Date, 17 August 2020
2.0 Public Announcement, 20 August 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 encrypt your message
using security-officer at 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-2020-8620 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.
More information about the bind-announce
mailing list