The encrypted email service Tutanota, received DDoS attacks this week, targeting first the company site and then the providers DNS. These attacks resulted in millions of users not being able to access the service for many hours. The shutdown of the service was further aggravated by the fact that different DNS servers continued to cache incorrect entries for domain.
Tutanota is a German provider of end-to-end encrypted email service, with more than 2 million users. The company is often listed along with popular encrypted email providers such as Protonmail. The Tutanota service is based on open source code and exchanges encrypted emails with anyone, easily and quickly. Thus, all user messages and contacts are stored encrypted on Tutankhamun systems. The decryption of users' messages and contacts is done only with the password set by each user. No one else knows him and no one has access to a user's data, except the user himself. The Tutanota service combines the ease of use of email with safety and encryption for all. Therefore, it enables users to take the security of their messages into their own hands.
The TDanota DDoS attacks took place on September 12-13, causing problems for hundreds of users. However, the security incidents were rectified immediately by restricting an "overreacting IP-block" that was responsible for attack.
Tutanota said in a blog post that this weekend the ongoing DDoS attacks and an infrastructure issue have led to downtimes for hundreds of users. The company added that although it mitigated most DDoS, an overreacting IP-block to combat attacks prevented hundreds of users from accessing Tutanota for several hours this Sunday.
In addition, the post mentions many measures and improvements against DDoS, implemented by the company, through which it is expected to facilitate the restoration of any future disturbances that may arise from DDoS attacks. Instead of focusing on the "collapse" of Tutanota servers directly, the attackers decided to use alternative means.
The second DDoS attack hit the DNS provider hosting registrations for Tutanota.
As a result, this provider "fell". The company immediately tried to update the DNS records and transfer them to another provider. This did not work at first because DNS entries were locked to one of the DNS hosting providers.
Tutanota co-founder Matthias Pfau told BleepingComputer it was a direct attack on everyone's freedom and right to privacy. With Tutanota, the company provides a safe tool to millions of users around the world, including activists and journalists. These ongoing attacks on Tutanota seem to have only one goal: to prevent citizens from using encrypted email, according to Pfau.
The company confirmed that the service was restored on Thursday, September 17 at 7:30 CET.
Due to the holidays, however, enough messages Emails sent to Tutanota users may not have been delivered. However, Tutanota assured its users that they were not violated data and that the end-to-end encrypted nature of the service makes it impossible even for the company itself to access user data.
Pfau said that as the company improves its system for mitigating DDoS attacks, attackers appear to be looking for other ways to harm it. He added that since this is a service that focuses on privacy, using a mitigation service that requires its SSL key for their service is not an option. This is the challenge of creating a secure email service that respects privacy. But the company will succeed, as it managed not to use services Google, like Google push for its Android application, Pfau stressed.