How to remediate – Fortinet FortiOS User Interface Default Credentials

1. Introduction

The Fortinet FortiOS User Interface Default Credentials vulnerability allows attackers to gain administrative access to Fortinet devices using pre-set, known credentials. This poses a critical risk as it enables unauthorized control of network security infrastructure. Affected systems typically include FortiGate firewalls and other appliances running vulnerable versions of FortiOS, potentially impacting the confidentiality, integrity, and availability of network resources.

2. Technical Explanation

The vulnerability stems from the use of default administrative login credentials on the web-based management interface of Fortinet FortiOS devices. An attacker who can access this interface can attempt to log in using these known defaults. Successful authentication grants full administrative control over the device.

• Root cause: The remote FortiOS user interface ships with a default set of credentials that are not changed during initial setup.
• Exploit mechanism: An attacker attempts to login to the web interface using the default username and password. If successful, they gain administrative access. For example, an attacker could use a simple HTTP request with the correct credentials in the authentication header.
• Scope: Fortinet FortiOS devices running vulnerable versions of the user interface are affected.

3. Detection and Assessment

To confirm vulnerability, check the current configuration for default credentials or identify the FortiOS version. A thorough assessment involves attempting to log in with known defaults.

• Quick checks: Use the web interface to view the system information which will display the running FortiOS version.
• Scanning: Nessus vulnerability ID bd132450 can be used as an example for detecting this issue.
• Logs and evidence: Examine logs for failed login attempts using default credentials, though successful logins may not always be logged clearly.

fortioscli version

4. Solution / Remediation Steps

The primary solution is to change the default admin login credentials immediately. Follow these steps for a secure remediation.

4.1 Preparation

• Change window needs and approval: A standard change window may be appropriate depending on your organization’s policies.

4.2 Implementation

1. Step 1: Log in to the FortiOS web interface as an administrator.
2. Step 2: Navigate to System > Admin > User.
3. Step 3: Select the ‘admin’ account.
4. Step 4: Change the password to a strong, unique value.
5. Step 5: Confirm the new password and save the changes.

4.3 Config or Code Example

Before

admin / default_password

After

admin / new_strong_password

4.4 Security Practices Relevant to This Vulnerability

Practices that directly address this vulnerability include strong password policies and secure defaults. Least privilege can also reduce the impact if an account is compromised.

• Practice 1: Implement a strong password policy requiring complex passwords with regular rotation.

4.5 Automation (Optional)

Automation is not generally recommended for credential changes due to security concerns, but configuration management tools can be used to enforce password complexity policies.

# Example Ansible snippet (use with caution and secure variable handling):
- name: Ensure admin password meets complexity requirements
  ansible.builtin.command: fortioscli config user setting admin password "{{ new_password }}"

5. Verification / Validation

• Post-fix check: Attempt to login using ‘admin’ and ‘default_password’. Access should be rejected.
• Re-test: Re-run the steps in Section 3; default credentials should no longer grant access.
• Smoke test: Verify that you can still log in with the new password and access key features of the web interface.

Attempt to login via web interface - Access Denied

6. Preventive Measures and Monitoring

Update security baselines to include a requirement for changing default credentials. Implement checks in deployment pipelines to enforce password complexity policies. A regular patch cycle helps address vulnerabilities like this one.

• Baselines: Update your FortiOS security baseline or policy to require immediate credential changes upon deployment.
• Pipelines: Add a check during CI/CD to verify that default credentials are not present in configuration files.
• Asset and patch process: Implement a regular patch review cycle for FortiOS devices, prioritizing critical vulnerabilities like this one.

7. Risks, Side Effects, and Roll Back

Changing the password incorrectly can lock out administrative access. Ensure you have documented the new password securely. If locked out, restore from backup.

• Risk or side effect 1: Incorrectly entered password may result in account lockout.
• Risk or side effect 2: Loss of access if new password is forgotten and not documented.

8. References and Resources

• Vendor advisory or bulletin: http://www.nessus.org/u?bd132450
• NVD or CVE entry: N/A (This is a known default credential issue, not a specific CVE)
• Product or platform documentation relevant to the fix: https://docs.fortinet.com/document/fortios/7.2/administration-guide/admin-users