Imagine someone trying to pick a lock on a door. If they find the right key but stop turning it halfway, the security system watching the door doesn’t realize they’ve succeeded. Sounds like a major loophole, right? That’s exactly what’s happening with Fortinet’s VPN systems—a tool companies use to securely connect their employees to private networks.
A recent discovery shows that hackers can exploit a design flaw in Fortinet’s VPN. This flaw allows them to figure out valid usernames and passwords without setting off any alarms in the system. Here’s a breakdown of what’s happening, why it’s concerning, and how businesses can stay protected.
What Is Fortinet VPN?
Fortinet’s VPN is widely used by companies to let their employees access their work network securely, especially when working remotely. Think of it as a digital tunnel that keeps sensitive information safe from prying eyes.
The Problem: A Sneaky Loophole
Here’s where things go wrong. Normally, a VPN system should record every login attempt—whether it succeeds or fails—so security teams can monitor for suspicious activity. But with Fortinet’s VPN, it only logs a “successful login” after two steps[1]:
- Authentication: Checking if the username and password are correct.
- Authorization: Confirming the user has permission to access the network.
Hackers have found that if they stop the process after step one (authentication) but before step two (authorization), the system doesn’t record it as a successful login. Instead, it looks like just another failed attempt. This allows hackers to test a bunch of passwords, figure out the right one, and go undetected.
Why This Matters
For businesses, this is a serious risk. Security teams rely on logs to detect when something suspicious is happening, like someone trying to guess passwords [2]. If successful attempts are hidden, hackers can quietly collect valid login credentials and return later to access the network—this time without any barriers.
It’s like giving someone a chance to practice unlocking your door without you ever noticing.
How Can Businesses Protect Themselves?
Here are some steps businesses can take to reduce the risk:
- Enable Multi-Factor Authentication (MFA): Even if someone guesses a password, they’ll still need a second form of verification, like a code sent to the user’s phone.
- Monitor for Unusual Activity: Security teams should look for patterns like multiple failed login attempts, which could signal someone testing passwords.
- Apply Security Updates: If Fortinet releases a fix for this flaw, it’s crucial to install it right away.
Final Thoughts
This flaw in Fortinet’s VPN system is a wake-up call for businesses to strengthen their cybersecurity defenses. Hackers are always looking for creative ways to bypass security, and this loophole is a clear example of how they can stay one step ahead if companies aren’t vigilant.
Citations:
1. Pentera. (n.d.). FortiClient VPN logging blind spot revealed. Retrieved November 21, 2024, from https://pentera.io/blog/FortiClient-VPN_logging-blind-spot-revealed/
2. BleepingComputer. (n.d.). Fortinet VPN design flaw hides successful brute-force attacks. Retrieved November 21, 2024, from https://www.bleepingcomputer.com/news/security/fortinet-vpn-design-flaw-hides-successful-brute-force-attacks/