Fortinet FortiOS < 6.0.10 / 6.2.x < 6.2.4 / 6.4.x < 6.4.1 Improper Authentication (FG-IR-19-283)

critical Nessus Plugin ID 141122
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The remote host is affected by an improper authentication vulnerability.


The remote host is running a version of FortiOS prior to 6.0.10, 6.2.x prior to 6.2.4, or 6.4.x prior to 6.4.1. It is, therefore, affected by an improper authentication vulnerability due to an issue with the 'username-case-sensitivity' CLI attribute for the SSL VPN. An unauthenticated, remote attacker can exploit this, by changing the case of the username, to log in without being prompted for FortiToken 2FA.


Upgrade to Fortinet FortiOS version to 6.0.10, 6.2.4, 6.4.1 or later, or apply the workaround from the advisory.

See Also

Plugin Details

Severity: Critical

ID: 141122

File Name: fortios_FG-IR-19-283.nasl

Version: 1.14

Type: local

Family: Firewalls

Published: 10/2/2020

Updated: 8/12/2021

Dependencies: fortinet_version.nbin

Risk Information

CVSS Score Source: CVE-2020-12812


Risk Factor: Critical

Score: 9.5


Risk Factor: High

Base Score: 7.5

Temporal Score: 5.5

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

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


Risk Factor: Critical

Base Score: 9.8

Temporal Score: 8.5

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

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

Vulnerability Information

CPE: cpe:/o:fortinet:fortios

Required KB Items: Host/Fortigate/version, Host/Fortigate/model

Exploit Ease: No known exploits are available

Patch Publication Date: 7/24/2020

Vulnerability Publication Date: 7/24/2020

Reference Information

CVE: CVE-2020-12812

IAVA: 2020-A-0440-S