Be careful, because you are conflating separate and unrelated issues.
The DNC hack and the hack on Hillary's e-mail server are quite probably the result of Russian hackers, based on everything I've been reading. Those are HACKS, not DDOS attacks. Completely different animal.
A HACK is an unauthorized attempt (successful or not) to gain access to restricted resources (e-mail, files, databases, servers, PCs, laptops, etc.)
A DDOS is in many ways the exact OPPOSITE; it is an attempt to PREVENT access to resources by ANYONE. In this sense, changing a password could be viewed as a DDOS, if doing so prevents normally authorized people from having access.
So far, there have been THREE different DDOS attacks of unprecedented volume:
- krebsonsecurity.com - taken down by a DDOS attack involving at least 150,000 IOT devices, peaking at 620 Gb/s of throughput. Thought to be in retaliation for Brian Krebs' expose on the authors of vDOS, a DDOS-tool-for-hire service. The attack was so large that Akamai, which had been providing DDOS mitigation services to him for free, had to stop because it was overloading their service and affecting paying customers. Krebs is now using Google's Project Shield.
- OVH - a French ISP targeted by a DDOS attack that exceeded 1100 Gb/s. I have not been able to find a reason for this attack. They suffered multiple attacks over a 48-hour period. Best guess is that some site they host was the actual target of the attack. It occurred at the same time as the Krebs attack.
- DYN DNS - a commercial DNS service, was severely impacted by a massive DDOS attack involving "10s of millions of discrete IP addresses associated with the Mirai botnet that were part of the attack." The motivation of this attack is unknown, but one thought is that it was aimed at Sony's PSN.
There are lots of DDOS attacks happening all over the world at any given time; you can see a map
here. These were different because of the fact that:
- They were larger than anything ever seen before
- They were found to be using botnets of compromised and relatively unsophisticated devices: web cams, dvd players, routers, and other IoT (Internet of Things) devices.
TBH, the Krebs attack makes sense to me. The others, not so much. I can't help but wonder if they weren't a smokescreen for something else.
I mean, think about it. If you had command of a botnet like this, and you were a bad guy, you could very VERY easily use it to hold a network hostage. But it hasn't been used that way. If <I> were behind this, and I had these kinds of resources to play with, <I'D> sure as heck use it as a smokescreen so that I could hack something more important at my leisure.