Denial of Service - What is a Denial of Service (DoS) attack?

Essentially if you suffer a DoS attack you will be denied either a resource or service which you normally get via the Internet, e.g. email. If you have a web site such attacks could mean that it is inaccessible and files and systems could also be damaged or indeed destroyed. These security breaches can be very expensive for the companies involved through loss of time and revenue and indeed in terms of customer confidence. There are many different types of attack.

Denial of Service Attacks Defence

Firstly check for any security holes which would allow entry to your systems, ensuring that your Firewall capabilities include DoS protection. As with all security, planning for an attack is better than responding in the aftermath of a Denial of Service breach of security.

Types of DoS Attack

SYN Flood Attack
This is a type of DoS attack where the attacker sends a huge amount of please-start-a-connection packets then nothing else. These Flood Attacks block up the flow of sessions and deny your own communications.

Teardrop Attacks
Most systems are set up to break down large packets to suitable sizes for each system, and the fragments are uniquely marked so that they can be reassembled at the receiving end. A Teardrop DoS attack puts different markers on the fragments so they cannot be identified and this can result in a system crashing as it cannot resolve the differing markers.

These are just a couple of the types of DoS attack that have been identified, suffice it to say these attacks can be very expensive and should be guarded against as part of a planned security process.