String of attacks disrupts other cloud services, including Evernote.

News aggregator Feedly was made inaccessible by attackers who are demanding a ransom to stop their crippling assault. Two other cloud-based servers, Evernote and Deezer, have also buckled under distributed denial of service (DDoS) attacks in recent days.

Most or all of Feedly's 12 million or so users were unable to access its website early Wednesday morning. A few hours later, parts of the site gradually came back online. In an advisory, officials wrote:

2:04am PST – Criminals are attacking feedly with a distributed denial of service attack (DDoS). The attacker is trying to extort us money to make it stop. We refused to give in and are working with our network providers to mitigate the attack as best as we can.

We are working in parallel with other victims of the same group and with law enforcement.

We want to apologize for the inconvenience. Please know that your data is safe and you will be able to re-access your feedly as soon as the attack is neutralized.

On Tuesday, Evernote also experienced connectivity problems that it attributed to DDoS attacks. The service seemed to be working normally as of press time. Cloud-based music service Deezer suffered a DDoS attack over the weekend, according to The Inquirer, which cited e-mails company officials sent to subscribers.

Over the past few years, DDoS attacks have grown increasingly powerful. According to the Verizon Data Breech Investigations Report published in April, the size of the average attack more than doubled from 2011 to 2013, from 4.7Gbps to 10.1Gbps. Attacks of 100 Gbps are regular occurrences these days, and Internet-threatening torrents of 400Gbps have also been documented. The increasing firepower is the result of attackers tapping super botnets made up of servers, which have orders of magnitude more bandwidth and processing power than more traditional PC botnets. DDoS attacks have also grown fiercer thanks to automated exploit kits available in underground forums and the increasing use of amplifications methods such as those that abuse the Internet's network time protocol and poorly secured domain name system servers.
Denial of service attacks are the modern-day equivalent of a caveman wielding a club. They require little skill, and they generally aren't hacking, since they don't bypass a target's security. Still, they remain an effective way to get the attention of millions of people. For that reason, they're not likely to go away any time soon.