Powerful DDoS Attack Cripples ProtonMail Service For Days

Geneva-based encrypted email service ProtonMail has been offline for most of the past two days after being targeted by what the company is calling an “extremely powerful DDoS attack.”

The email service, developed by CERN scientists, was knocked offline on Nov. 3 when attackers started flooding their IP addresses with bogus traffic. Soon after, the company said the attack expanded to the datacenter in Switzerland where the its servers are located, and the service was interrupted.

The company was not able to stop the attack, but has been working around the clock to get the email service back online. The ProtonMail team managed to restore service briefly on Wednesday, but a new round of DDoS attacks took it down again, the company announced on Twitter. 

Another DDOS. All data is secure and untouched, but access to the site is unlikely. We’re working with our datacenter to solve this.

— ProtonMail (@ProtonMail) November 4, 2015

Following its tweet, the company posted a series of updates on the social networking platform, informing users that the attack was ongoing. ProtonMail reported this morning that another attack was conducted while they were trying to restore the service, and they are still offline at the time of publishing.

In a blog post, the company explained that the attack took down several other tech companies as well, along with some banks. They also noted that all user data is secure thanks to the implemented end-to-end encryption, although access to the server is limited.

“To solve this problem we are working with the top companies and people both onsite in our Swiss data center and from around the world. We are confident we will be back online – we just wish it was sooner rather than later,” the company said. In the blog post, the company also appeals to users who have experience with mitigating enterprise level DDOS attacks to help it fend off the intrusion. Additionally, it announced on Twitter that it was looking for a datacenter in Switzerland to move its service to.

We are seeking a datacenter in Switzerland brave enough to host ProtonMail, many are afraid due to the magnitude of the attack against us.

— ProtonMail (@ProtonMail) November 5, 2015

DDoS attacks have seen an increase in the past quarters, and a recent report from Kaspersky Lab revealed that almost half of those carried out in the third quarter have been launched from Linux-based botnets. Most notable in the timeframe was the XOR DDoS botnet, which was used to launch 150+ gigabit-per-second (Gbps) DDoS attacks.