CVE-2020-8617: A logic error in code which checks TSIG validity can be used to trigger an assertion failure in tsig.c
ISC BIND is vulnerable to a denial of service, caused by a logic error in code which checks TSIG validity. A remote attacker could exploit this vulnerability to trigger an assertion failure in tsig.c.
Other sources
Using a specially-crafted message, an attacker may potentially cause a BIND server to reach an inconsistent state if the attacker knows (or successfully guesses) the name of a TSIG key used by the server. Since BIND, by default, configures a local session key even on servers whose configuration does not otherwise make use of it, almost all current BIND servers are vulnerable. In releases of BIND dating from March 2018 and after, an assertion check in tsig.c detects this inconsistent state and deliberately exits. Prior to the introduction of the check the server would continue operating in an inconsistent state, with potentially harmful results.
— Launchpad
Affected Software
Remediation
Patch Available
Patch Available
Information
Event History
Frequently Asked Questions
What is CVE-2020-8617?
CVE-2020-8617 is a vulnerability in ISC BIND that allows an attacker to cause a denial-of-service by exploiting a logic error in the code that checks TSIG validation.
How severe is CVE-2020-8617?
CVE-2020-8617 has a severity score of 7.5 out of 10, indicating a high severity vulnerability.
Which software versions are affected by CVE-2020-8617?
CVE-2020-8617 affects BIND versions 9.0.0 to 9.11.18, 9.12.0 to 9.12.4-p2, 9.13.0 to 9.13.7, 9.14.0 to 9.14.11, 9.15.0 to 9.15.6, 9.16.0 to 9.16.2, and 9.17.0 to 9.17.1.
How can I fix CVE-2020-8617?
To fix CVE-2020-8617, it is recommended to upgrade to the patched versions of BIND: 9.11.5.P4+dfsg-5.1+deb10u7 or later for Debian, and follow the guidance provided by the vendor for other affected software.
Where can I find more information about CVE-2020-8617?
You can find more information about CVE-2020-8617 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](http://packetstormsecurity.com/files/157836/BIND-TSIG-Denial-Of-Service.html).