Fortios
CVE-2020-12812
CRITICAL
Severity by source
AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Primary rating from NVD · only source for this CVE.
CVSS VectorNVD
Lifecycle Timeline
3DescriptionNVD
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.
AnalysisAI
FortiOS SSL-VPN contains an improper authentication vulnerability that allows users to bypass two-factor authentication by changing the case of their username, undermining MFA security controls.
Technical ContextAI
The CWE-178 case-sensitivity flaw means the 2FA lookup treats 'admin' and 'Admin' as different users. The password validation is case-insensitive (matching the AD backend), but the FortiToken association lookup is case-sensitive. Logging in with a different-case username passes password auth but skips the 2FA check.
RemediationAI
Upgrade FortiOS immediately. Review VPN authentication logs for case-variant login attempts. Ensure all remote access requires properly enforced MFA that cannot be bypassed through case manipulation.
An authentication bypass using an alternate path or channel [CWE-288] in Fortinet FortiOS version 7.2.0 through 7.2.1 an
FortiOS and FortiProxy contain an authentication bypass via the Node.js websocket module allowing unauthenticated remote
A out-of-bounds write in Fortinet FortiOS versions 7.4.0 through 7.4.2, 7.2.0 through 7.2.6, 7.0.0 through 7.0.13, 6.4.0
A heap-based buffer overflow vulnerability [CWE-122] in FortiOS version 7.2.4 and below, version 7.0.11 and below, versi
Fortinet FortiAnalyzer before 5.0.12 and 5.2.x before 5.2.5; FortiSwitch 3.3.x before 3.3.3; FortiCache 3.0.x before 3.0
Buffer overflow in the Cookie parser in Fortinet FortiOS 4.x before 4.1.11, 4.2.x before 4.2.13, and 4.3.x before 4.3.9
Cross-site scripting (XSS) vulnerability in the sslvpn login page in Fortinet FortiOS 5.2.x before 5.2.3 allows remote a
FortiOS and FortiProxy contain an authentication bypass allowing unauthenticated attackers with knowledge of upstream/do
An Exposure of Sensitive Information to an Unauthorized Actor vulnerability [CWE-200] vulnerability in Fortinet FortiOS
Use of a hard-coded cryptographic key to cipher sensitive data in FortiOS configuration backup file may allow an attacke
Arbitrary file write and folder deletion in Fortinet FortiManager, FortiOS, and FortiProxy is possible via a path traver
A buffer underwrite ('buffer underflow') vulnerability in the administrative interface of Fortinet FortiOS version 7.2.0
Same weakness CWE-178 – Improper Handling of Case Sensitivity
View allSame technique Authentication Bypass
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External POC / Exploit Code
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