CVE-2020-12812 : An improper authentication vulnerability in SSL VPN in FortiOS 6.4.0, 6.2.0 to 6

An improper authentication vulnerability in SSL VPN in FortiOS 6.4.0, 6.2.0 to 6.2.3, 6.0.9 and below may result in a user being able to log in successfully without being prompted for the second factor of authentication (FortiToken) if they changed the case of their username.

Published 2020-07-24 23:15:12

Updated 2024-02-13 17:25:59

Source Fortinet, Inc.

View at NVD, CVE.org

Vulnerability category: BypassGain privilege

Products affected by CVE-2020-12812

Fortinet » Fortios
Versions before (<) 6.0.10
cpe:2.3:o:fortinet:fortios:*:*:*:*:*:*:*:*
Matching versions
Fortinet » Fortios
Versions from including (>=) 6.2.0 and before (<) 6.2.4
cpe:2.3:o:fortinet:fortios:*:*:*:*:*:*:*:*
Matching versions
Fortinet » Fortios » Version: 6.4.0
cpe:2.3:o:fortinet:fortios:6.4.0:*:*:*:*:*:*:*
Matching versions

CVE-2020-12812 is in the CISA Known Exploited Vulnerabilities Catalog

This issue is known to have been leveraged as part of a ransomware campaign.

CISA vulnerability name:

Fortinet FortiOS SSL VPN Improper Authentication Vulnerability

CISA required action:

Apply updates per vendor instructions.

CISA description:

Fortinet FortiOS SSL VPN contains an improper authentication vulnerability that may allow a user to login successfully without being prompted for the second factor of authentication (FortiToken) if they change the case in their username.

Notes:

https://nvd.nist.gov/vuln/detail/CVE-2020-12812

Added on 2021-11-03 Action due date 2022-05-03

Exploit prediction scoring system (EPSS) score for CVE-2020-12812

EPSS FAQ

2.92%

Probability of exploitation activity in the next 30 days EPSS Score History

~ 90 %

Percentile, the proportion of vulnerabilities that are scored at or less

CVSS scores for CVE-2020-12812

Base Score	Base Severity	CVSS Vector	Exploitability Score	Impact Score	Score Source
7.5	HIGH	AV:N/AC:L/Au:N/C:P/I:P/A:P	10.0	6.4	NIST
Access Vector: Network Access Complexity: Low Authentication: None Confidentiality Impact: Partial Integrity Impact: Partial Availability Impact: Partial
9.8	CRITICAL	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H	3.9	5.9	NIST
Attack Vector: Network Attack Complexity: Low Privileges Required: None User Interaction: None Scope: Unchanged Confidentiality: High Integrity: High Availability: High

CWE ids for CVE-2020-12812

CWE-178 Improper Handling of Case Sensitivity

The product does not properly account for differences in case sensitivity when accessing or determining the properties of a resource, leading to inconsistent results.

Assigned by: nvd@nist.gov (Primary)
CWE-287 Improper Authentication

When an actor claims to have a given identity, the product does not prove or insufficiently proves that the claim is correct.

Assigned by: nvd@nist.gov (Primary)

References for CVE-2020-12812

https://fortiguard.com/psirt/FG-IR-19-283

FortiOS SSL VPN 2FA bypass by changing username case | FortiGuard
Vendor Advisory