Urgent Security Alert: Fortinet Devices Under Widespread Brute-Force Attack
Cybersecurity teams are on high alert following reports of a large-scale, global campaign targeting Fortinet devices. Threat actors are actively engaged in widespread brute-force attacks aimed at gaining unauthorized access to networks protected by FortiGate firewalls and other Fortinet appliances. This activity represents a significant and immediate threat to organizations of all sizes.
The primary target of this campaign is exposed FortiGate SSL-VPN interfaces. By relentlessly guessing usernames and passwords, attackers are attempting to compromise valid user credentials. A successful breach provides a direct gateway into a corporate network, potentially leading to data theft, ransomware deployment, and further malicious activity.
Understanding the Threat: What is a Brute-Force Attack?
A brute-force attack is a straightforward yet often effective method used by cybercriminals. It involves systematically trying countless combinations of usernames and passwords until the correct one is found. In this current campaign, threat actors are leveraging automated scripts to rapidly test common, weak, or previously compromised credentials against Fortinet VPN portals.
It is crucial to understand that this attack does not exploit a new software vulnerability. Instead, it preys on weak or reused passwords and a lack of fundamental security controls. Any organization with an internet-facing Fortinet VPN that relies solely on single-factor authentication (a password only) is at a heightened risk of compromise.
How to Protect Your Network: Essential Security Measures
Proactive defense is the only way to mitigate this threat. If your organization uses Fortinet products, especially for remote access, it is imperative to review your security posture immediately. The following steps are critical to hardening your defenses against these ongoing attacks.
1. Enable Multi-Factor Authentication (MFA)
This is the single most effective defense against brute-force and credential-stuffing attacks. MFA requires a second form of verification—such as a code from a mobile app or a physical security key—in addition to a password. Even if an attacker successfully guesses a password, they cannot gain access without the second factor. All user accounts, especially those with administrative privileges, must be protected with MFA.
2. Enforce a Strong Password Policy
Ensure all users are required to create complex and unique passwords. A strong password policy should include:
- A minimum length of 12-14 characters.
- A mix of uppercase letters, lowercase letters, numbers, and symbols.
- A prohibition against using common or easily guessable words.
- Regular password rotation schedules.
3. Implement Account Lockout Policies
Configure your Fortinet devices to automatically lock an account after a specific number of failed login attempts. For example, locking an account for 15 minutes after five incorrect password entries can dramatically slow down and deter automated brute-force attacks, making them impractical for the attacker to continue.
4. Monitor and Analyze Logs
Actively monitor your system logs for signs of an attack. Pay close attention to a high volume of failed login attempts, especially from unfamiliar IP addresses or geographic locations. Suspicious login patterns are a clear indicator of malicious activity and should trigger an immediate investigation.
5. Restrict Access with Geo-IP Filtering
If your business operates within specific countries or regions, use Geo-IP filtering to block all login attempts from outside those areas. This simple step can eliminate a massive volume of automated attacks originating from foreign threat actors.
6. Keep Firmware and Software Updated
While this specific campaign targets credentials, maintaining up-to-date firmware is a cornerstone of good security hygiene. Always apply the latest security patches from Fortinet to protect against known vulnerabilities that could be exploited in future attacks.
The threat is active and ongoing. Taking these defensive measures is not just recommended—it is essential for protecting your network perimeter and safeguarding your organization’s sensitive data. Don’t wait for a breach to happen. Review your Fortinet security configurations and implement these critical protections today.
Source: https://www.helpnetsecurity.com/2025/08/14/brute-force-attacks-hammer-fortinet-devices-worldwide/
