ISC BIND 9.14.x < 9.16.6, 9.17.x < 9.17.4 DoS

high Nessus Plugin ID 139916
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Synopsis

The remote name server is affected by a denial of service vulnerability.

Description

According to its self-reported version number, the installation of ISC BIND running on the remote name server is version 9.14.x prior to 9.16.6 or 9.17.x prior to 9.17.4. It is, therefore, affected by a denial of service (DoS). While query forwarding and QNAME minimization are mutually incompatible, BIND did sometimes allow QNAME minimization when continuing with recursion after 'forward first' did not result in an answer. In these cases the data used by QNAME minimization might be inconsistent, leading to an assertion failure. An unauthenticated, remote attacker can exploit this issue by triggering the condition to cause the server to crash. Servers that forward only are not affected.

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

Solution

Upgrade to BIND 9.16.6, 9.17.4 or later.

See Also

https://kb.isc.org/docs/cve-2020-8621

Plugin Details

Severity: High

ID: 139916

File Name: bind9_9174_cve_2020_8621.nasl

Version: 1.3

Type: remote

Family: DNS

Published: 8/27/2020

Updated: 6/3/2021

Dependencies: bind_version.nasl

Configuration: Enable paranoid mode

Risk Information

CVSS Score Source: CVE-2020-8621

VPR

Risk Factor: Low

Score: 3.6

CVSS v2

Risk Factor: Medium

Base Score: 4.3

Temporal Score: 3.2

Vector: AV:N/AC:M/Au:N/C:N/I:N/A:P

Temporal Vector: E:U/RL:OF/RC:C

CVSS v3

Risk Factor: High

Base Score: 7.5

Temporal Score: 6.5

Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Temporal Vector: E:U/RL:O/RC:C

Vulnerability Information

CPE: cpe:/a:isc:bind

Required KB Items: bind/version, Settings/ParanoidReport

Exploit Ease: No known exploits are available

Patch Publication Date: 8/20/2020

Vulnerability Publication Date: 8/20/2020

Reference Information

CVE: CVE-2020-8621

IAVA: 2020-A-0385-S