Distributed denial of service (DDoS) is one of the most destructive threats on the Internet. The 2007 Computer Crime and Security Survey published by the Computer Security Institute reported that 25 per cent of its 500 respondents had experienced a DDoS attack, with total losses amounting to $2.9 million.
By flooding Internet-facing servers with fake page requests from thousands of sources at the same time, DDoS attacks stop real requests getting through and can bring the entire infrastructure to its knees. The largest attacks can generate upwards of 20Gbps of fraudulent requests, which is enough to overwhelm nearly any network. DDoS can put web sites, applications and IP telephony services out of actions for weeks.
DDoS is not new but the last 24 months has seen attacks become more virulent, sophisticated and targeted at a wider range of companies. Until 2006, few companies outside of the media, gaming, finance and payment services industries would have been targets, but now DDoS attacks are being used even to take out a competitor’s web presence.
Attacks are typically launched by botnets, vast networks of compromised PCs. Access to these are sold on to the highest bidder, making it simple and cheap to launch DDoS attacks. More sophisticated attacks emulate real requests making it extremely difficult to root out the malicious traffic.
It’s not just high-volume attacks that are causing havoc, however, other criminals are using low-volume attacks aimed at applications servers to bypass any DDoS protection companies may have.
Stopping DDoS attacks is unfortunately not straightforward. Off-the-shelf appliances are available that can help block fake requests, but it’s a running battle with criminals who come up with ever new approaches to disguise their traffic. Managed services are also available that take a company’s entire traffic during an attack and scrub out the malicious traffic, while returning the valid requests. This has the advantage of freeing up the victim’s network from the volume of traffic an attack generates.
Whatever the approach to solving DDoS attacks, there’s no doubt that companies across all industries now need to consider how they will protect themselves. DDoS attacks are cheap to launch, can be very expensive to stop, and can cause untold damage to a company’s business and reputation.