What are DoS and DDos attacks?
A Denial of Service-attack (DoS, not DDoS) is the disruption of normal operations bij servers provided to users. This can be done using to methods, there is third, but the third requires physical access to networking components involving the server or it's connection. Mostly 'big targets' are attacked, but a DoS attack at your computer, or rather, your router can also cause serious problems.
Basic methods to perform a DoS attack
- Overloading the server or one of it's central components. This can be accomplished by: - overloading the cpu, -overloading the memory, -flooding the server with data causing loss of bandwith, or by filling up the harddrive of the server
- Editing essential informations such as dns/routing settings, though these can only be changed when using exploits or when the server is misconfigured or badly secured
The effects are, mostly, the same, user experience extremely bad connection to the surfer under attack, or no connection at all. The above is a DoS-attack, explained, because a DDoS attack is a DoS-attack only Distributed, hence the extra 'd'. So how does a DDoS-attack work?
A DDoS-attack works the same way as a DoS-attack, the main difference is, it's distributed, meaning more people take part in the attack, no matter where they are. This way a group of people from The US can combine with a group of people from Saudia-Arabia to attack a server in, let's see, erm The Hague, for example. There are no border limitations whatsoever so an attack can be set-up globally. Though, most of the time Distributed DDoS attacks are not executed by people willing to participate in one.
To perform a DDoS-attack usually one, or a few, people combine forces to write a virus or Trojan horse, sometimes installing a backdoor, this way the creators of the malware gain, partial, control over the infected computers. There are two main methods a DDoS attack can take place:
- The malware contains a code telling the infected computers to 'attack' a certain ipaddress, at a given time/date. When a lot of computers are infected, a great ammount of computerpower is focused at the 'victim' and the attack can be a success, with the 'victim' not even knowing who really set-up this attack since his/her ip wasn't involved in the attack, only those of the infected devices.
- The malware contains code telling the infected computers to log on to a botnet. This way the creator of the code gains realtime control over a lot of infected machines who are esentially zombies, brain-dead, since when do computers have brains, devices at the mercy of the creator of the code. The creator can do anything with these zombies, having a very powerfull tool.
What can I do against my computer being compromised? Well, as you can read in most of the articles, good virus protection and a good firewall are essential and keep all programs and your operating-system up-to-date so minimum risk is involved. Secondly, when you notice a lot of internet activity and neither your firewall, nor your antivirus program has warned you about anything, something might be wrong. Check tos ee if you haven't got a download or upload going on, when you don't go here.