What is DoS Attack?
DOS is an attack used to deny legitimate users access to a resource such as accessing a website, network, emails, etc. or making it extremely slow. DoS is the acronym for Denial of Service. This type of attack is usually implemented by hitting the target resource such as a web server with too many requests at the same time. This results in the server failing to respond to all the requests. The effect of this can either be crashing the servers or slowing them down.
Cutting off some business from the internet can lead to significant loss of business or money. The internet and computer networks power a lot of businesses. Some organizations such as payment gateways, e-commerce sites entirely depend on the internet to do business.
In this tutorial, we will introduce you to what denial of service attack is, how it is performed and how you can protect against such attacks.
Types of Dos Attacks
There are two types of Dos attacks namely;
- DoS– this type of attack is performed by a single host
- Distributed DoS– this type of attack is performed by a number of compromised machines that all target the same victim. It floods the network with data packets.
DoS attack tools
The following are some of the tools that can be used to perform DoS attacks.
- Nemesy– this tool can be used to generate random packets. It works on windows. This tool can be downloaded from http://packetstormsecurity.com/files/25599/nemesy13.zip.html . Due to the nature of the program, if you have an antivirus, it will most likely be detected as a virus.
- Land and LaTierra– this tool can be used for IP spoofing and opening TCP connections
- Blast– this tool can be downloaded from http://www.opencomm.co.uk/products/blast/features.php
- Panther– this tool can be used to flood a victim’s network with UDP packets.
- Botnets– these are multitudes of compromised computers on the Internet that can be used to perform a distributed denial of service attack.
DoS Protection: Prevent an attack
An organization can adopt the following policy to protect itself against Denial of Service attacks.
- Attacks such as SYN flooding take advantage of bugs in the operating system. Installing security patches can help reduce the chances of such attacks.
- Intrusion detection systems can also be used to identify and even stop illegal activities
- Firewalls can be used to stop simple DoS attacks by blocking all traffic coming from an attacker by identifying his IP.
- Routers can be configured via the Access Control List to limit access to the network and drop suspected illegal traffic.