What is a Denial of Service Attack?

A denial-of-service, or “DoS” attack, is a type of cyber attack that prevents legitimate users from accessing computer systems, services, devices, or other network resources. Attackers make these resources inaccessible by flooding the network with traffic until it crashes. When malicious excess traffic comes from multiple sources, this is known as a distributed denial of service (or “DDoS” attack), which can be even more difficult to resolve and recover from.

Signs of a DoS Attack
The effects of a DoS/DDoS attack will depend on your perspective. For example, if you are a user of online banking and your institution’s network has been targeted, their website will likely stop responding. On the business side, the bank’s customer service representatives will find that the online systems they depend on to serve their customers cease to respond.

Preventing DoS Attacks
While DoS/DDoS attacks do not directly result in the theft of confidential information, organizations usually see a significant loss of productivity and money as a result of the downtime. While it is not possible to avoid becoming a target entirely, network security companies offer software that protects against network flooding by rerouting malicious traffic. Many firewalls also offer DoS detection functions and will help in restricting bandwidth usage to only legitimate users.