DoS vs. DDoS: A comparison and differences in the attacks
7 min read
A denial-of-service (DoS) attack, similarly to a distributed denial-of-service (DDoS) attack, can hinder the network and make it unavailable for users. However, here’s where their similarities end. Find out the main differences between DoS and DDoS and the best ways to prevent these attacks from impairing your network.
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DoS vs DDoS attacks: What are the main differences?
Both DoS and DDoS attacks aim to overload the servers of a particular system to make it unresponsive. The main difference between the two is that while a DoS attack hinders the targeted system using one device, DDoS attacks are conducted through multiple devices operating on different networks that usually form a botnet.
By using a number of remote devices at once, DDoS attacks send a higher volume of malicious traffic to the targeted system than DoS ever could. Devices used for DDoS attacks can originate in different locations, making it harder to locate the actual source of the attack.
Meanwhile, DoS attacks use a script or other specific tools to run the attack, achieving a comparatively lower attack volume and making the attacker more traceable.
| DoS attack | DDoS attack | |
|---|---|---|
| How does it work? | DoS attack floods the targeted network with malicious traffic coming from a single source | DoSS attack floods the targeted network with malicious traffic coming from several sources |
| What’s the source of the attack? | One machine or an IP | Various sources, including infected devices, botnets, and compromised IPs |
| Is it hard to execute? | Fairly easy to execute | Harder to execute, requires additional resources |
| Is it hard to detect? | Relatively easy to detect because the traffic comes from one source | Hard to detect because traffic may come from multiple sources and different locations |
| What impact does it have? | Limited impact | Severe impact |
What is a DoS attack?
A denial-of-service attack is a cyber-attack that floods the targeted servers with more User Datagram Protocol/Transmission Control Protocol (UDP and TCP) packets than the system can handle. It corrupts data, makes the system crash, or completely paralyzes it, making its network inaccessible to users. DoS attacks are fairly easy to operate and highly effective, which makes them one of the most prevalent cybersecurity threats.
What is a DDoS attack?
A distributed denial-of-service attack is a DoS attack that hampers the system by flooding it with malicious traffic through multiple computers or a botnet. A hacker behind the DDoS attack aims to spread the net of infected devices so that more computers would act as bots. Through them, hackers can send large amounts of internet traffic to the targeted system at once, rapidly overflowing it.
Hackers also try to infect devices originating in multiple locations because it helps disguise the actual location and device from which the attack is coordinated. Besides, with multiple devices in remote spots, attackers can launch their offensives much faster. These reasons make DoS and DDoS an attractive choice for cyberterrorism and other cyberwarfare practices.
DoS vs DDoS attacks: What are their main types?
DoS and DDoS attacks can transform into a number of specified offensives that target particular elements within the attacked system. These specialized attacks can be divided into four main types:
- Volume-based attacks. They overwhelm the targeted network’s bandwidth by flooding it with Internet Control Message Protocol (ICMP) echo requests or launching a UDP flood attack. Afterward, the network slows down or ceases to have any bandwidth left to use, making it inaccessible to users and their devices. It’s the most common type of DoS and DDoS attacks.
- Protocol attacks. These attacks exploit vulnerabilities in the connection between the protocol and the Open Systems Interconnection (OSI) model. Protocol attacks typically affect the OSI’s model layer 3, which is responsible for the data routing across networks, and layer 4, which controls the end-to-end connection. The most commonly exploited protocols are TCP, UDP, and ICMP. Depending on the protocol, hackers can target the handshake process between the protocol and the web server or the connection’s request and reply system.
- Application layer attacks. Application-based attacks target OSI’s model layer 7, responsible for all the system’s applications. The hacker usually sends an abundance of partial data packets to the application, which is unable to resolve them. This way, the application keeps getting flooded with unsolvable requests, and because of them, it cannot develop new legitimate connections. Application layer attacks are hard to detect because they use a minimum amount of bandwidth and don’t require many bots to launch the attack.
- IP fragmentation attack. During this attack, hackers resize IP packets so that the receiving end cannot assemble them and comprehend the data within. Afterward, the system starts failing because it tries to use all its resources to reassemble broken IP data packet fragments.
How to avoid DoS and DDoS attacks
Sneaky and devastating as they may seem, both DoS and DDoS attacks can be avoided or at least tamed using proper measures. The following prevention methods can help you avoid falling victim to denial-of-service attacks:
- Network monitoring. It’s common for attackers to test the network they plan to corrupt before launching a DoS campaign. If you regularly monitor your network, you’ll have more chances to recognize suspiciously increased online traffic and stop the attack at its roots.
- Test running DoS attacks. By simulating a denial-of-service attack, network owners can assess how effective their prevention apparatus is against it. It’s an important step in trying to build a robust prevention strategy.
- Assessing possible damage. After test-running a DoS attack, it’s essential to evaluate which assets would have suffered the most and pinpoint the network’s vulnerabilities.
- Creating a backup strategy. A clear plan of action in the event of a DoS or DDoS attack can help mitigate the damages to the targeted network and recreate the usual system operation in the shortest possible time.