CVE-2020-8617A logic error in code which checks TSIG validity can be used to trigger an assertion failure in tsig.c

Description

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.

Data: CVE.org, NVD, CISA KEV, FIRST EPSS, Ubuntu. Published as the sources state it, in English.

Affected products and versions

References and patches

• https://kb.isc.org/docs/cve-2020-8617
• [oss-security] 20200519 Two vulnerabilities disclosed in BIND (CVE-2020-8616 and CVE-2020-8617) mailing-list
• DSA-4689 vendor-advisory
• https://security.netapp.com/advisory/ntap-20200522-0002/
• http://packetstormsecurity.com/files/157836/BIND-TSIG-Denial-Of-Service.html
• USN-4365-2 vendor-advisory
• USN-4365-1 vendor-advisory
• [debian-lts-announce] 20200530 [SECURITY] [DLA 2227-1] bind9 security update mailing-list
• FEDORA-2020-2d89cbcfd9 vendor-advisory
• FEDORA-2020-f9dcd4e9d5 vendor-advisory
• openSUSE-SU-2020:1699 vendor-advisory
• openSUSE-SU-2020:1701 vendor-advisory