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FortiauthenticatorApplication · Fortinet

CVE-2021-43067

MEDIUM · 6.5 CVSS v3.1 Published 2021-12-08
Fix available
A fix is available. Upgrade to after 6.0.7 or later.
See remediation →
72/100
Remediation priority · Elevated
Remotely reachable No privileges

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
A exposure of sensitive information to an unauthorized actor in Fortinet FortiAuthenticator version 6.4.0, version 6.3.2 and below, version 6.2.1 and below, version 6.1.2 and below, version 6.0.7 to 6.0.1 allows attacker to duplicate a target LDAP user 2 factors authentication token via crafted HTTP requests.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

FortiAuthenticator versions 6.4.0 through 6.0.1 contain an information disclosure vulnerability where crafted HTTP requests allow unauthenticated attackers to duplicate LDAP users' 2-factor authentication tokens. This enables unauthorized replication of sensitive 2FA credentials.

MitigationUpgrade FortiAuthenticator to the vendor patched version. Prioritize remediation given the CVSS 6.5 score and the exposure of 2FA tokens enabling potential account takeover.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
FortiauthenticatorApplication
Affected:>= 6.0.1, <= 6.0.7= 6.1.0= 6.1.1= 6.1.2= 6.2.0= 6.2.1= 6.3.0= 6.3.1= 6.3.2= 6.4.0

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
Required
Scope
Unchanged
Confidentiality
High
Integrity
None
Availability
None

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify FortiAuthenticator installation
    Locate the FortiAuthenticator system on your network. This is typically a dedicated appliance or virtual machine. Confirm the device hostname and management IP address.
    Affected if FortiAuthenticator is present and accessible on the network
  2. Determine installed FortiAuthenticator version
    Log into the FortiAuthenticator web GUI or CLI and navigate to System > Dashboard > System Information widget, or run 'get system status' via CLI to retrieve the firmware version.
    Affected if The version falls within 6.0.1 through 6.0.7, or is exactly 6.1.0, 6.1.1, 6.1.2, 6.2.0, 6.2.1, 6.3.0, 6.3.1, 6.3.2, or 6.4.0
  3. Verify LDAP user synchronization is enabled
    In the FortiAuthenticator GUI, go to LDAP Users > LDAP Users and confirm at least one LDAP directory is configured and users are being synchronized. Alternatively, check via CLI with 'show user ldap'.
    Affected if LDAP directories are configured and LDAP users exist in the system
  4. Confirm 2FA is configured for LDAP users
    Navigate to Authentication > User Management > LDAP Users and verify that two-factor authentication is enabled for the LDAP users or LDAP user groups. Check the 2FA method configured (FortiToken, email, SMS, etc.).
    Affected if Two-factor authentication is enforced for LDAP synchronized users
  5. Inspect HTTP access logs for unusual requests
    In the FortiAuthenticator GUI, go to Log & Report > Event Log > Authentication and search for duplicate or repeated authentication attempts targeting LDAP user endpoints. Look for unauthenticated requests to endpoints like /mfa/ or /api/v1/mfa/.
    Affected if Unauthenticated or anomalous HTTP requests targeting MFA/token endpoints appear in logs

Your environment is affected if FortiAuthenticator versions 6.0.1 through 6.4.0 are running with LDAP user synchronization and 2FA enabled for those LDAP users.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to a release after 6.0.7
Interim mitigation

Upgrade FortiAuthenticator to the vendor patched version. Prioritize remediation given the CVSS 6.5 score and the exposure of 2FA tokens enabling potential account takeover.

Recommended fix Moderate confidence

FortiAuthenticator 6.4.0 or later

  1. 1. Back up the FortiAuthenticator configuration before proceeding with any upgrade.
  2. 2. Review the FortiAuthenticator upgrade guide and release notes for version 6.4.0 or later.
  3. 3. Plan for maintenance window as the upgrade may require downtime.
  4. 4. Download the FortiAuthenticator firmware version 6.4.0 or later from the Fortinet support portal.
  5. 5. Upload and install the firmware upgrade following Fortinet's standard upgrade procedures.
  6. 6. After upgrade, verify that LDAP user 2-factor authentication functionality is working correctly.
  7. 7. Confirm the vulnerability is remediated by reviewing system logs and testing the 2FA token duplication scenario.
Caveat Review release notes for any configuration or feature changes between your current version and 6.4.0

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Fortiauthenticator Scoped from the published advisory
  • Consultation4.0 h
  • Implementation6.0 h
  • Testing8.0 h
  • Review / QA4.0 h
22.0 hours of engineering $3,800
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2021-43067 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data