#VU28123 Reachable Assertion in ISC BIND

Published: 2020-05-26 | Updated: 2020-06-03

Vulnerability identifier: #VU28123

Vulnerability risk: Medium

CVSSv3.1: 7 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:F/RL:O/RC:C]

CVE-ID: CVE-2020-8617


Exploitation vector: Network

Exploit availability: Yes

Vulnerable software:
Server applications / DNS servers

Vendor: ISC


The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.

The vulnerability exists due to a reachable assertion when checking validity of messages containing TSIG resource records within tsig.c. A remote attacker can send a specially crafted message and 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.

Install updates from vendor's website.

Vulnerable software versions

ISC BIND: 9.0.0 - 9.17.1

External links

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability. However, a fully functional exploit for this vulnerability is available.

Latest bulletins with this vulnerability