What Is Internet Denial of Service?

Denial of service is a malicious attack on a website.

Internet denial of service is a method used to maliciously attack a website, rendering it unusable. Commonly referred to as DoS, these types of attacks can even disrupt the operation of major websites.

Denial of Service

Flooding a server is the most common type of denial of service attack. A server is flooded with requests to view a website. This overwhelms the server and prevents legitimate requests to view the site from reaching it.

Distributed Denial of Service

Distributed Denial of Service, or DDoS, refers to another type of denial of service attack. This type of attack occurs when other machines previously infected with malicious software are controlled remotely by an attacker to overwhelm a website. The controlled computers in this type of attack are commonly referred to as a bot-net or a zombie network.

Email Bomb

Email bombing is another type of denial of service attack. It essentially works the same way. An email server or email address is spammed and flooded with emails until it can no longer handle the load, preventing legitimate emails from getting through.

Motivations

According to CNET, the most common motivation for using a DoS attack is money. Criminals often use this tactic to blackmail e-businesses in return for regaining the functionality of their websites. However, some attacks are done for purely malicious purposes, and others are done for notoriety.

Prevention

DoS attacks are not limited to only businesses and websites. A personal computer can become involved in a DoS attack. According to the United States Computer Emergency Readiness Team (US-CERT), there are no effective ways to ensure you are not a victim. However, installing and maintaining anti-virus software and a firewall can reduce the likelihood of your computer being used in an attack. US-CERT also recommends being diligent about how you distribute your email address.

References

• CNET: How a "Denial of Service" Attack Works
• CNET: Security From A to Z: DDoS
• US-CERT: Cyber Security Tip ST04-015

Resources

• Internet Engineering Task Force: Internet Denial-of-Service Considerations