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Difference between DOS and DDOS attack

By IncludeHelp Last updated : July 27, 2024

In today's digital era, network security is more critical than ever. We must be aware of some common types of cyberattacks, including Denial of Service (DoS) and Distributed Denial of Service (DDoS) Attacks. In this tutorial, we will deal with these two types of attacks in detail.

What is a Denial of Service (DoS) Attack?

A Denial of Service (DoS) attack is a cyberattack in which the attacker attempts to make a network, or service inaccessible to its authorised users. This can be done by flooding the target with unauthorised requests, causing the system to slow down or fail.

Common Types of DoS Attacks

There are different types of Denial of Service (DoS) attacks, each serving a specific purpose:

1. Flooding Attacks

Flooding attacks are a type of DoS attack where bots flood the network with traffic, causing the target website to crash due to more requests.

Example:

Imagine you have a store and suddenly thousands of people try to enter at once. The store can't handle the crowd, and genuine customers can't get in. Bots act like these people in a flooding attack, overwhelming the website with fake requests.

2. SYN Flood Attacks

SYN flood attacks refer to sending excessive SYN packets to the target system. SYN packets are used to build a connection, but when too many are sent, the target system doesn't respond to legitimate requests.

Example:

Let's take a phone system where someone keeps dialing but never completes the call. The system gets stuck handling these unfinished calls and can't take new calls. In a SYN flood attack, the attacker sends numerous SYN packets, overloading the target server.

What is a Distributed Denial of Service (DDoS) Attack?

A Distributed Denial of Service (DDoS) attack is a cyberattack in which multiple infected systems flood a target system with excessive traffic. This disrupts the system very badly.

Common Types of DDoS Attacks

Some of the common types of DDOS attacks are:

1. Volumetric Attacks

These attacks flood the target with overwhelming traffic, using a botnet, to exhaust its resources and bandwidth.

2. Protocol Attacks

Exploits flaws in the TCP connection process, like the three-way handshake, to keep ports busy and inaccessible, ultimately shutting down the server.

3. Application Attacks

Targets specific applications, like websites, by flooding them with bad requests, making it difficult for the victim to respond.

4. Fragmentation Attacks

Manipulates the breaking down process and reassembling data packets, causing confusion and rendering them unable to be properly reassembled. This disrupts the communication across the network.

Differences between DoS and DDoS attacks

The key differences between DoS and DDoS attacks are explained below in the table:

Aspect	DoS Attack	DDoS Attack
Meaning	A single source floods a target with traffic.	Multiple sources coordinate to flood a target with traffic.
Source	Usually one computer or network.	Coordinated from multiple computers or networks, forming a botnet.
Intensity	Typically less intense compared to DDoS.	More intense due to multiple sources, capable of overwhelming targets.
Impact	Can disrupt services for a single user or system.	Can cause widespread disruptions affecting entire networks or services.
Detection	Easier to detect and mitigate due to a single source.	Difficult to detect due to the distributed nature and multiple sources.
Example	Flooding a website with traffic from one computer.	Coordinated attack flooding a website from hundreds of infected computers.

Case Study: DoS Attack

XYZ Clothing, an online store, faced a sudden surge in website traffic due to a new marketing campaign. A dissatisfied ex-employee flooded XYZ Clothing's website with traffic from a single source, overwhelming the server and causing it to crash.

Impact

• Loss of sales and revenue
• Damage to reputation
• Financial costs for investigation and mitigation

Solution

Identified and blocked the attacker, and implemented additional security measures.

Case Study: DDoS Attack

GameWorld, an online gaming platform, hosted a major gaming tournament with thousands of players.Hackers used a botnet to flood GameWorld's servers with massive traffic, disrupting gameplay and causing severe lag and disconnections.

Impact

• Disrupted gaming experience
• Reputation damage
• Financial losses from refunds and future revenue

Solution

Mitigated the attack with filtering techniques and rerouting, collaborated with law enforcement, and invested in network infrastructure and DDoS mitigation.