Why the NordVPN network is safe after a third-party provider breach

Timeline

1. The affected server was brought online on January 31st, 2018.
2. Evidence of the breach first appeared on May 3rd, 2018. That evidence indicated that the breach is likely to have occurred on or around March 5th, 2018.
3. The breach was restricted when the data center deleted the undisclosed unsecure management account on March 20th, 2018.
4. We were notified about the breach on April 13, 2019. We shredded the server that same day.

Key facts

• One server was affected in March 2018 in Finland. The rest of our service was not affected. No other servers of any type were put at risk. This was an attack on our server, not our entire service.
• The breach was made possible by poor configuration on a third-party datacenter’s part that we were never notified of. Evidence suggests that when the datacenter became aware of the intrusion, they deleted the accounts that had caused the vulnerabilities rather than notify us of their mistake. As soon as we learned of the breach, the server and our contract with the provider were terminated and we began an extensive audit of our service.
• No user credentials were affected.
• There are no signs that the intruder attempted to monitor user traffic in any way. Even if they had, they would not have had access to those users’ credentials.
• The attacker did acquire TLS keys that, under extraordinary circumstances, could be used to attack a single user on the web using a specifically targeted and highly sophisticated MITM attack that we detail further below. These keys could not and cannot be used to decrypt any encrypted NordVPN traffic in any form.
• Two other VPN providers were impacted in attacks published by the same intruder. We do not believe that this was a targeted attack against NordVPN.
• The incident effectively showed that the affected server did not contain any user activity logs. To prevent any similar incidents, among other means, we encrypt the hard disk of each new server we build. The security of our customers is the highest priority to us and we will continue to raise our standards further and further.

Here’s the full story along with more technical information:

A few months ago, we became aware of an incident in March 2018 when a server at a datacenter in Finland we had been renting servers from was accessed without authorization. This was done through an insecure remote management system account that the datacenter had added without our knowledge. The datacenter deleted the user accounts that the intruder had exploited rather than notify us.

The intruder did not find any user activity logs because they do not exist. They did not discover users’ identities, usernames, or passwords because none of our applications send user-created credentials for authentication.

The intruder did find and acquire a TLS key that has already expired. With this key, an attack could only be performed on the web against a specific target and would require extraordinary access to the victim’s device or network (like an already-compromised device, a malicious network administrator, or a compromised network). Such an attack would be very difficult to pull off. Expired or not, this TLS key could not have been used to decrypt NordVPN traffic in any way. That’s not what it does.

This was an isolated case, and no other servers or datacenter providers we use have been affected.

Once we found out about the incident, we first terminated our contract with the provider and eliminated the server, which we had operated since January 31, 2018. We then immediately launched a thorough internal audit of our entire infrastructure. We had to ensure that no other server could possibly be exploited this way. Unfortunately, thoroughly reviewing the providers and configurations for over 5,000 servers around the world takes time. As a result, we decided we should not notify the public until we could be sure that such an attack could not be replicated anywhere else on our infrastructure. Lastly, we raised our standards even further for current and future datacenter partners to ensure that no similar breaches could ever happen again.

We want our users and the public to accurately understand the scale of the attack and what was and was not at risk. The breach affected one of over 3,000 servers we had at the time for a limited time period, but that’s no excuse for an egregious mistake that never should have been made. Our goal is not to undermine the severity and significance of this breach. We should have done more to filter out unreliable server providers and ensure the security of our customers.

Since the discovery, we have taken all the necessary means to enhance our security. We have undergone an application security audit, are working on a second no-logs audit right now, and are preparing a bug bounty program. We will give our all to maximize the security of every aspect of our service, and next year we will launch an independent external audit of all of our infrastructure.

Our goal here is to notify and educate the public about this breach. That’s the only way we’ll be able to recover from this significant setback and make our security even tighter.

NOTE: Post updated 10/25/2019.

UPDATE (10/26/2019): We've published a detailed plan for how we're going to improve our security following this incident. Click here to check it out.

Is NordVPN still hacked?

UPDATE (11/13/2020): NordVPN is not hacked and there is no evidence that any user data ever was hacked during this incident. Our service is currently fully secure.

Now that some time has passed since this security issue, it's worth repeating a few key points:

• There is and was no evidence that any user data was affected. Over a year has passed since the issue was resolved, and no further findings have surfaced to suggest otherwise.
• The issue was resolved immediately after it was detected and has remained so to this day. We have updated our processes to ensure that this type of vulnerability cannot occur again.
• Since then, we have taken a number of steps to significantly improve our security beyond anything prescribed by this security issue specifically. We've launched a successful bug bounty program, we're moving to colocated servers, and we have a number of other projects in the works that we'll be excited to announce when the time is right.