A Denial of Service Attack (DoS) is when a server is placed under great strain by overloading it with substantial traffic, causing it to slow to a crawl or crash. This makes the service unavailable for legitimate users.

Distributed Denial of Service Attacks (DDoS) are when the requests come from multiple different locations at once, making it more difficult to separate the legitimate traffic from the malicious. A DDoS attack usually utilises a Botnet such as the GameOver Zeus Botnet. Botnets are networks of computers that have been infected with malware, usually without the knowledge of the computer owners. The malware can then silently install and run software on these computers in the background that allows a remote user to control the individual computers.

This can allow a cyber thief access to sensitive data, such as online banking login credentials, or files containing other personal information. Alternatively, the computers in the botnet can be used in DoS attacks, by “pinging” remote servers. Using a botnet in this way can send a server offline – disrupting businesses and public services.

Major businesses are not immune to these threats. Recently, Sony’s Playstation Network, which allows owners of Playstation consoles to play multiplayer games online, was sent offline by a DDoS attack, meaning legitimate paying customers were unable to use the service. Other businesses and services that have been hit in the past include Visa, Mastercard, Amazon, and PayPal.

What are the implications of being hit by a DDoS Attack?

Having your business disrupted by a Denial of Service attack has similar implications to any kind of downtime. There won’t be any actual damage done to your infrastructure, but this doesn’t mean there won’t be costs. Downtime is very costly. The damage to your reputation could be severe, depending on the length of the downtime. In 2011, Sony’s Playstation Network was down for three weeks. If your business succumbs to this kind of attack, the majority of paying customers won’t understand that it wasn’t your fault – they will just be annoyed that they can’t use your service, and may consider using a rival company. In Sony’s case, this could have contributed to some gamers potentially defecting to a rival console such as Microsoft’s Xbox when the time came to upgrade.

Lost revenue during the outage is also a concern for many businesses that suffer downtime. Consider Amazon and Paypal, who were both hit by DoS attacks. You may think that the loss of revenue would not have been that great, as customers would just make their purchases at a later time when the service was available again. However, for a large number of transactions this would not be the case. When customers are in the mood to buy, they will often find what they want and buy it elsewhere if they are unable to buy it from their first choice of retailer. The failure of that retailer to meet their needs would also probably be remembered the next time that customer wanted to buy something. If the competitor was able to offer a great service, the repeat customer might be lost for good.

How can businesses defend themselves from DDoS Attacks?

If your business has a reliable IT support partner, there are a variety of measures that can be taken to effectively mitigate DDoS attacks. The first step is ensuring that there are measures in place to detect an attack as soon as possible. There are simple scripts that can be run on a server that monitor the load placed on that server, and can send you an alert if the traffic spikes significantly or if the script fails.

Simply blocking the IP addresses of the attackers would be a virtually impossible method of mitigating a DDoS attack, since the attack will come from so many different IP addresses at once. However, IT support staff with the right technical knowledge, can use software to examine the packets of data that are sent to your server and spot commonalities, then configure your firewall or route to block traffic with these patterns.

The severity of an attack can even be lessened by having the right equipment and infrastructure in place in the first instance. This is where the technology consulting aspect of outsourced IT can be of great benefit, as you should be set up to cope with these types of attacks more effectively. Certain firewalls, such as Sonicwall, can help prevent certain types of denial of service attacks, and can help you to manage against others.

Another way of managing DDoS attacks is to have more than enough bandwidth on your webserver than you usually need. That way you can simply absorb the attack without too much impact. Be wary of this method however, as it can result in unexpectedly high bandwidth charges.