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ProtonMail hit by mystery DDoS attack, preventing customers from accessing their secure email


November 05, 2015

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ProtonMail hit by mystery DDoS attack, preventing customers from accessing their secure email

End-to-end encrypted email service ProtonMail is suffering from an “extremely powerful” distributed denial-of-service attack, that has knocked it offline, and stopped users from accessing their inboxes.

Switzerland-based ProtonMail has its fair share of fans amongst those who wish to keep their communications secret and secure, as its architecture is designed to never give ProtonMail any method of decrypting your messages, even if they were to receive demands from law enforcement agencies – but clearly the DDoS attack shows that not everyone is a fan.


In a blog post, ProtonMail explains that the attack began on Tuesday November 3rd, firstly flooding its IP addresses and then targeting the Swiss data centre where it houses its servers. According to the firm, the websites of several other tech companies and even some banks were also disrupted as a result of the internet attack.

Although ProtonMail says that it is working hard to restore normal operations, at the time of writing the ProtonMail site remains offline.


On its website (when it’s online) ProtonMail boasts about the security of its data centre:

“Our primary data centre is located under 1,000 meters of granite rock in a heavily guarded bunker which can survive a nuclear attack.”

But such physical security is no barrier for hackers hell-bent on launching a denial-of-service attack. Customers who are affected are advised to follow ProtonMail’s Twitter account for updates.

One of the most frequent security models you will hear about is the CIA triad: Confidentiality, Integrity and Availability.

In many people’s eyes ProtonMail scores well on confidentiality and integrity, but with it being struck so hard by the DDoS attack it is failing at the moment when it comes to availability.

After all, what use is a secure email service if you can’t access your emails?

Fortunately, a denial-of-service attack may prevent users from reaching their inboxes, but it wouldn’t in itself indicate a breach of ProtonMail’s security or that hackers have been able to access users’ messages.

We hope that ProtonMail, who are – we shouldn’t forget – the victims of a criminal attack, are able to restore their systems to normal operation sooner rather than later.

In the meantime, however, it seems that a legitimate question to ask is this:

Who on earth would be keen to disrupt access to a secure email service, and potentially put it out of business?

Leave your opinion and conspiracy theories as a comment below…




Graham Cluley is an award-winning security blogger, researcher and public speaker. He has been working in the computer security industry since the early 1990s.

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