DoS and DDoS Attack - The Key Differences Explained

As organisations become fully automated and handle everything online, threats and security issues are growing. Attacks like DoS and DDoS are some of the common risks they face. In this blog, we will explore DOS and DDoS attacks, their types and other aspects related to them.

Table of Contents

• What is a DoS Attack?
• What is a DDoS Attack?
• Difference Between DoS and DDoS Attack
• Types of DoS Attack
• Types of DDoS Attack
• How to Prevent DoS and DDoS Attacks
• Conclusion

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What is a DoS Attack?

The first step to understanding the difference between DoS and DDoS attacks is to understand what a DoS attack is (Denial of Service attack). The following section will elucidate the same.

In a Denial of Service attack, a site or server is filled with overwhelming or inorganic bot traffic by a third party. The third party is usually an attacker with malicious intentions.

The overwhelming traffic can be generated up to several gigabytes per second.

Every site or server is built with a certain level of hosting capacity, and traffic is generated to exceed this limit. When the limit is exceeded, organic or real users have trouble accessing the site; the access is denied or the server or site crashes.

The generated inorganic traffic usually comes with no return address and, thus, makes the resolving time longer. This is because, without a return address, the server or site cannot send authentication certification to verify the source. It is important to note that the traffic continues to accumulate until the host resolves the issue completely.

A DoS attack has an upgraded version in the industry as well; this is known as a DDoS attack. The following section will briefly elucidate what is a DDoS attack.

What is a DDoS Attack?

The next step to understanding the difference between a DoS and a DDoS attack is to understand what is a DDoS attack (Distributed Denial of Service attack). The following section will elucidate the same.

A DDoS attack is similar to a DoS attack but differs slightly. The difference between DoS and DDoS attacks is that, usually, a DDoS attack happens from multiple resources, while a DoS attack happens from a single IP address. Furthermore, the difference between DoS and DDoS attacks is evident through the intention of the attack. A DoS attack happens intentionally, while a DDoS attack can happen without malicious intention as well.

For example, if a page becomes popular overnight, it could witness heavy user activity. When the user traffic is more than the site’s capacity, the page could crash, leading to organic users having trouble accessing the site.

This happens to small pages where the host has designed the site with limited capability. Large-scale business pages, especially shopping sites, experience crashes of the exact nature when there is a sale.

Briefly, the difference between DoS attacks and DDoS attacks can be understood via the following section.

Difference Between DoS and DDoS Attack

Types of DoS Attack

The next step is to understand different types of DoS and DDoS attacks. The following section will elucidate the same.

Denial of Service attacks are primarily of two types.

1. Application Attacks

Application Denial of Service attacks, also called Layer 7 attacks, target the operations of the site or server. By generating traffic to the extent that the site or server can no longer process any new requests, the operations of the site or server are forced to be stopped.

2. Network Attacks

Similar to application attacks, network attacks generate massive targets toward the host site or server. Network attacks saturate the host’s bandwidth with bot or inorganic requests. Currently, network Denial of Service Attacks are tackled with firewall configuration.

Apart from this, some other dos attacks are.

Yo-yo Attack

This is a type of Distributed Denial of Service attack that predominantly aims at cloud-hosted applications. The DDoS attacker generates massive traffic and invades space, and when the host out scales to handle the attack, the DDoS attacker stops the attack. The attack resumes the attack when the host moves forward from the attacked space.

Briefly, it can be said that once the host believes that the site is safe, the attack will resume, and this cycle will continue. Yo-yo DDoS attacks result in financial issues for the host.

Advanced persistent DoS Attack

Commonly known as APDoS, an advanced persistent DoS attack can last for weeks and generate over 50,000 TB of inorganic or bot traffic. The prolonged attack is achieved by creating a diversion by attacking other sources. This means that the attacker will target a main server or site and will attack other sites till the host cools off the countermeasures. By the time the host believes the attack to be gone, the attack will start again.

The following are the current common types of DDoS attacks.

Types of DDoS Attacks

1. HTTP Flood

When HTTP gets or posts requests to enter into a server, network, or site with the motive to shut it down, it is known as an HTTP flood Distributed Denial of Service attack. The requests appear to be legitimate, and the attack does not require techniques such as malformed packets, reflection, or spoofing.

The attack reaches its maximum potential by forcing the server to allocate maximum resources to resolve all requests effectively.

2. Slowloris

When an attack enables a web server to attack another web server, it is known as a slow loris attack. This attack is initiated by sending partial requests to the target site. When the server keeps such partial requests open, more attacks will be generated by the attacker toward the target till the maximum process level is reached by the server. On reaching the maximum process level, the site will begin to deny further requests, including organic requests.

3. UDP Flood

This attack is initiated by flooding UDP packets at random ports of the target site. When the host tries to locate or resolve the issue, it will not be found. When the attack and the unsuccessful resolve mechanism cycle continue, the attack will successfully sap the host’s resources. As a result, the site will be inaccessible to organic or real visitors.

It is important to protect your site and your organization’s network from such attacks.

But how? The following section will elucidate various tips on how to prevent DoS and DDoS attacks.

How to Prevent DoS and DDoS Attacks

The following suggestions will help you to prevent these attacks:

• Invest in anti-DDoS and anti-DoS attack services that help recognize such attacks by analyzing network traffic.
• If you suspect or conclusively find that your company server is under such an attack, then contact your internet service provider and discuss whether such traffic can be rerouted.
• Check if black-hole routing can be done; it is where the traffic is rerouted to a null route. This helps in protecting your site from crashes.
• Develop a DoS or DDoS response plan. This is helpful for big organizations. The development of a DDoS response plan includes allotting a dedicated team to monitor the security or potential of a DDoS attack in an organization.

Conclusion

The major difference between DoS and DDoS attacks is the attacking source and intensity. Comparatively, the effect of a DDoS attack is more severe than that of a DoS attack. However, it is important to build strong countermechanisms to protect your organization from such attacks.