A brief update regarding ongoing DDoS incidents

Share this page

As few weeks back, we sent a notice to the Proton community regarding the DDoS attacks that we have been facing. Today we would like to provide a brief update of the situation.

  • Starting on June 27th, Proton Mail started to be hit by sustained DDoS attacks.
  • The attack campaign continues to this day, but there has been little to no user impact.
  • Thus far the attacks have included:
    • Rapidly morphing DDoS attacks with the combination of SYN floods, TCP handshake violations (first packets are not SYNs), IPv4 TCP SYN floods, TCP Zero Sequence, ACK Floods, NTP nonstandard port floods, and reflection attacks on SSDP, NTP, Chargen, LDAP and Memcache protocols.
    • Pulsed/Burst DDoS attacks, with multiple attack vectors and rapid changes within minutes.
    • Attacks up to 25Gbs in volume. This attack was largely challenging to handle because of its complexity, not the size/volume. No unknown attack vectors were used, but they were rapidly changing, and hence the complexity.

Since November 2015, Proton Mail has been protected by Radware’s Cloud DDoS Protection Services, and in this instance, Radware was able to successfully mitigate nearly all of these attacks. However, due to the nature of the ferocity and attack ingenuity, some of the attacks were only partially mitigated and briefly resulted in some service outages at the outset of the campaign.

In order to improve mitigation performance, Radware immediately upgraded their scrubbing centers and processes to provide better protection against rapidly changing attacks. As a result, attack mitigation through the upgraded Radware scrubbing center has been successful in the past couple weeks.

After the upgrade, we have found that Radware’s technology actually works well against rapidly evolving attacks, and the automatic mitigation capabilities are essential for reducing the response times when coming under attack frequently. We also deeply appreciate the support that we have received from the team at Radware, and the fact that they made defending Proton Mail a priority. Going forward, we plan to utilize a multi-layered DDoS defense strategy and will continue to partner with Radware on the first line of defense.

We appreciate your patience through these attacks and look forward continuing to provide you with secure and private email services.

Protect your privacy with Proton
Create a free account

Share this page

Proton Team

We are scientists, engineers, and specialists from around the world drawn together by a shared vision of protecting freedom and privacy online. Proton was born out of a desire to build an internet that puts people before profits, and we're working to create a world where everyone is in control of their digital lives.

Related articles

With over 33 million registered users and more than 100,000 business customers, LastPass is one of the world’s most popular password managers. After an escalating series of highly-damaging disclosures over the last few months, LastPass has now admitt
Email headers are the hidden part of emails containing vital information to identify and authenticate messages. Learn how to read them to spot spam and stay secure. Have you received an unexpected email from a strange address? Is it actually from so
The United States is notoriously weak on privacy laws. With its secret surveillance courts and all-powerful spy agencies, the US has many tools to collect data on people within its jurisdiction and beyond. Recently, that power has been used to prose
When you encrypt files on your computer, it’s like storing them in a vault: Only someone with the correct key can access them. That’s useful if you’re concerned about hackers stealing your most sensitive documents or companies scanning your data for
Two-factor authentication (2FA) is an extra layer of protection for online accounts that requires you to use more than just your username and password to log in.  With 2FA enabled, you can protect access to your online accounts even if your password
Internet users of a certain age might recall earlier days of personal computing, with stacks of labeled floppy disks or CDs lying around the office. Those have all but disappeared thanks to the widespread availability of cloud storage, which took off