What are DDoS attacks?

In the last days numerous online shops were hit by DDoS attacks. The attackers sent countless data packages to the server systems of the affected companies causing their online shops to be completely down at times.

DDoS stands for «Distributed Denial of Service». The term describes overburdened computer systems and networks, which can no longer perform the tasks they have been set up to do because of massive, highly coordinated attacks. For the affected companies this means that their website can no longer be accessed. The consequences are lost profit and annoyed customers.

Attacks targeting infected computers are most common

In practice, DDoS attacks are executed in very different ways. In most cases the attackers use countless private computers to accomplish their malicious goal. They install malware on the computers and exploit them for their attacks. Often 50,000 or more computers are employed simultaneously (botnet). A control program coordinates the attacks and pass on the commands to the computers, which in turn start requesting the targeted website. Most of the time, this happens without the knowledge of the affected computer owners.

Attacking is easier than defending

DDoS attacks are problematic in more than one way: any company is able to rent a botnet on the black market in order to attack a selected website. The rental charges are quite low and the damage done to a competitor significant. On top of that comes the fact that the attacks are easier to set up than a defence. The attackers can vary their attacks to see what type of defence has been put in place and then adapt to this quite aptly. In most cases affected companies can thus only attempt to minimise the damage caused.