(Distributed) Denial of Service attacks, intentional or otherwise.

So, I have been away for a bit and thus the lack of posting. So to make that up, there will be two posts today and at least one more this week. Right, lets get into its shall we? Today's topic is (Distributed) Denial of Service attacks and how they can be inadvertently caused. So, first off, what exactly is is a Denial of Service (DoS) and indeed a Distributed Denial of Service (DDoS) attack.

A Denial of Service (DoS) attack involves sending an excessive amounts of data/requests/pings to a server with the aim of overloading the server so that legitimate users can not access the server. Imagine the following scenario: there is an office with an information counter. Normally, people would walk up tot he counter, get the information they need and then leave. After this the next person does the same and so on and so forth. A DoS would essentially be one person standing at the counter and asking so many questions that nobody else can get up to the counter.

A Distributed DoS (DDoS) is the same thing, except with one minor difference. In a standard DoS, there is only one attacker and one attacking system. In a DDoS, there may still be one attacker, but there are several systems that involved in the attack. For all intents and purposes, DoS attacks really only exist in textbooks, so we will only consider DDoS attacks.

So, now that we know what DDoS attacks are, let's look at how they happen. The normal scenario is that our attacker(s) pick a target and then bombard them with request. At a technical level, there are several ways to this in an intelligent ways, but the simplest is just overwhelming the server with requests. I would rather not get into the details, because to be quite honest, I find them inane and boring. SO, let's just say there are many ways of doing it.

Now, if you recall I did say we were going to discuss how one may inadvertently perform a DDoS. First off, we need to realise that different websites require different levels of hardware. Right at the top you have the likes of Google, who require server farms of sizes that are difficult to fathom. Then you go down to the bottom, where you have tiny websites that get a couple of hits a week, which probably run on a single machine. Obviously, the smaller the server, the easier it is to DDoS.Now, the unintentional DDoS attacks happen to theses smaller sites. How you ask? Well simple, they get very popular, very fast.

There a few ways you can achieve this. Firstly, start off a small website and then becomes popular. Then when you post new content, number of people accessing your site goes through the roof and your site becomes temporarily unavailable. Don't think this is possible? I refer you to a delightful webcomic (in a manner of speaking) The Oatmeal, run by Matthew Inman. He even says something about it on his Facebook page. He does somewhat DDoS himself, by being awesome!

Another way is best explained by using Stephen Fry as an example. Stephen had built up quite a fan base as an entertainer and television personality over the years, so when he ended up in Twitter, well naturally he had a smattering of followers (myself included). He is quite an avid user and apart from the usual tweets of his current activities (and of course his tweets for charity), he does tweet links to amusing content from time to time. The moment that tweet hits the net, there are thousands of people clicking that link and well it has caused more that one site to go down.

As we can see in both cases, neither party had any malicious intent towards the sites that they inadvertently DDoS'ed, but it did happen. The unfortunate part of this is that there is no way to defend against it. Well, there is the no practical way to defend against it. Of course, everybody could use industrial size server farms, but that is not really practical. There may be some sort of gains made if everything was hosted in the cloud, but I'm not sure how feasible that is.