CVE-2020-8622: A truncated TSIG response can lead to an assertion failure

Published Aug 21, 2020
·
Updated

In BIND 9.0.0 -> 9.11.21, 9.12.0 -> 9.16.5, 9.17.0 -> 9.17.3, also affects 9.9.3-S1 -> 9.11.21-S1 of the BIND 9 Supported Preview Edition, An attacker on the network path for a TSIG-signed request, or operating the server receiving the TSIG-signed request, could send a truncated response to that request, triggering an assertion failure, causing the server to exit. Alternately, an off-path attacker would have to correctly guess when a TSIG-signed request was sent, along with other characteristics of the packet and message, and spoof a truncated response to trigger an assertion failure, causing the server to exit.

Other sources

ISC BIND is vulnerable to a denial of service, caused by an assertion failure when attempting to verify a truncated response to a TSIG-signed request. By sending a specially-crafted request, a remote authenticated attacker could exploit this vulnerability to cause the server to exit.

IBM

Affected Software

23 affected componentsFixes available
IBM Cloud Pak for Security (CP4S)<=1.7.2.0
IBM Cloud Pak for Security (CP4S)<=1.7.1.0
IBM Cloud Pak for Security (CP4S)<=1.7.0.0
ISC BIND>=9.0.0<=9.11.21
ISC BIND>=9.12.0<=9.16.5
ISC BIND>=9.17.0<=9.17.3
ISC BIND=9.9.3-s1
ISC BIND=9.11.21-s1
Fedoraproject Fedora=31
Fedoraproject Fedora=32
Debian Debian Linux=9.0
Debian Debian Linux=10.0
Canonical Ubuntu Linux=12.04
Canonical Ubuntu Linux=14.04
Canonical Ubuntu Linux=16.04
Canonical Ubuntu Linux=18.04
Canonical Ubuntu Linux=20.04
NetApp Steelstore Cloud Integrated Storage
openSUSE Leap=15.1
openSUSE Leap=15.2
Synology DNS Server<2.2.2-5028
Oracle Communications Diameter Signaling Router>=8.0.0<=8.5.0
debian/bind9
1:9.16.50-1~deb11u21:9.16.50-1~deb11u41:9.18.41-1~deb12u11:9.18.44-1~deb12u11:9.20.18-1~deb13u11:9.20.20-1

Remediation

Information

Upgrade to the patched release most closely related to your current version of BIND: BIND 9.11.22 BIND 9.16.6 BIND 9.17.4 BIND Supported Preview Edition is a special feature preview branch of BIND provided to eligible ISC support customers. BIND 9.11.22-S1

Event History

Aug 21, 2020
CVE Published
via MITRE·08:50 PM
Data Sourced
via MITRE·08:50 PM
RemedyDescriptionSeverityWeakness
Feb 25, 2026
Data Sourced
via Ubuntu·12:54 AM
RemedyDescriptionSeverityAffected Software
Data Sourced
via Launchpad·12:55 AM
Description
Mar 15, 2026
Data Sourced
via Debian·01:09 AM
DescriptionAffected Software

Parent advisories

This vulnerability appears in the following advisories.

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Frequently Asked Questions

1

What is the severity of CVE-2020-8622?

The severity of CVE-2020-8622 is medium.

2

How does CVE-2020-8622 affect ISC BIND?

CVE-2020-8622 affects ISC BIND versions 9.0.0 to 9.11.21, 9.12.0 to 9.16.5, and 9.17.0 to 9.17.3.

3

How can an attacker exploit CVE-2020-8622?

An attacker on the network path for a TSIG-signed request, or operating the server receiving the TSIG-signed request, could send a truncated response to that request, triggering a denial of service.

4

Which software versions are affected by CVE-2020-8622?

ISC BIND versions 9.0.0 to 9.11.21, 9.12.0 to 9.16.5, and 9.17.0 to 9.17.3 are affected by CVE-2020-8622.

5

Where can I find more information about CVE-2020-8622?

You can find more information about CVE-2020-8622 in the references provided: [link1](http://lists.opensuse.org/opensuse-security-announce/2020-10/msg00041.html), [link2](http://lists.opensuse.org/opensuse-security-announce/2020-10/msg00044.html), [link3](https://kb.isc.org/docs/cve-2020-8622).

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