What Is DDoS?

A distributed denial of service, or DDoS, attack is a common type of cybersecurity threat that can significantly disrupt networks, services, and even entire businesses. The potential impact ranges from minor interference to system failures, leading to financial and reputational consequences for your organization.

In this post, we’ll explore what a DDoS attack is,  how it works, and different types of DDoS attacks. We’ll clarify the meaning of DDoS in the context of modern cybersecurity and provide essential best practices for how to stop DDoS attacks.

What is a DDoS attack?

A distributed denial of service (DDoS) attack is a malicious attempt to disrupt the normal operation of a server, network, or service by overwhelming it with massive internet traffic.

An example of a DDoS attack is sending too many requests to a web server causing the website to crash. Likewise, malicious actors can bombard a database with excessive search queries or data requests so that the database can’t handle the volume, leading to slowdowns or crashes, which can also disrupt any applications or websites relying on it.

Thousands of DDoS attacks are now reported each day, and most are mitigated as a normal course of business with no special attention warranted. But cyber attackers are capable of increasing the scope of the attack — and DDoS attacks continue to rise in complexity, volume, and frequency. This presents a growing threat to the network security of even the smallest enterprises.

Gartner, What is Cybersecurity

Since DDoS attacks disrupt services that customers rely on, they pose a significant threat to your organization’s reputation, customer satisfaction, and revenue. Therefore, it’s important to take preventive measures against DDoS attacks.

How does a DDoS attack work?

The key principle behind DDoS attacks is to overload the internet bandwidth, CPU, and RAM capacity of targeted networks and services in order to make them inaccessible.

Unlike simple denial of service (DoS) attacks, which come from one system, DDoS attacks leverage multiple systems or devices together. Cyber attackers access these systems by infecting various user devices with phishing attacks and other mass infection techniques. Called a botnet, these hundreds or thousands of bots await the malicious server’s command.

Once the command is given, the infected devices try to access the targeted resource all at once, overwhelming the system’s technical capacity to respond to legitimate requests. The flood of traffic consumes bandwidth and system resources, causing the target system to slow down, become inaccessible, or crash altogether.

It is extremely difficult — and frequently impossible — to filter out malicious traffic, as it usually comes from regular users’ infected devices widely distributed across the internet.

Types of DDoS attacks

There are several types of DDoS attacks, most of which fall into four main categories based on the component of the network connection they target.

• Volumetric attacks (or volume-based attacks) aim to saturate the target’s bandwidth and flood the network with large amounts of data.

Examples of volumetric attacks include UDP floods, ICMP floods, and DNS amplification.

Volume-based DDoS attacks are measured in bits per second (bps).

• Protocol attacks consume all server resources and disrupt the system by targeting specific network protocols and exploiting different network vulnerabilities.

Protocol DDoS attack examples include SYN floods, Smurf DDoS attacks, and IP fragmentation attacks.

Protocol DDoS attacks are measured in packets per second (pps).

• Application layer attacks (or resource layer attacks) target specific applications and services, overloading them with continuous requests until the server becomes unresponsive.

Examples of application layer attacks include HTTP floods, DNS query floods, and Slowloris attacks.

Application layer DDoS attacks are measured in requests per second (rps).

• Multi-vector attacks combine multiple attack methods in a single attack. Multi-vector attacks are harder to defend against, as they might target different layers of the system all at once.

If there are signs your network is under a DDoS attack, act fast, as hackers can make your organization vulnerable to other cyberattacks and threats.

How to prevent a DDoS attack

Preparing your organization ahead of time is key to prompt detection and response. To prevent a DDoS attack, consider the following best practices:

• Conduct a risk assessment. Regular risk assessments help you understand the vulnerabilities of your network’s hardware and software.
• Develop a denial-of-service defense strategy. Once the risks are identified, focus on the measures you need to take in order to promptly detect and prevent potential DDoS attacks.
• Update software regularly. Frequent updates help you address network vulnerabilities and make sure protection software works properly.
• Limit traffic rates. Reducing the number of requests that users and IP addresses can make within a certain time frame can help you significantly diminish the impact of bot traffic.
• Identify your regular traffic patterns. Establishing baselines for regular traffic patterns will allow you to detect anomalies that may signal a DDoS attack early on.
• Leverage a web application firewall (WAF). WAFs are effective against application layer attacks, as they analyze HTTP/HTTPS requests and block suspicious traffic.
• Implement a content delivery network (CDN). CDNs can absorb malicious traffic by balancing loads and distributing them between multiple servers globally.

How to detect and mitigate a DDoS attack

Detecting a DDoS attack may be challenging as most malicious traffic is usually dispersed and blended into legitimate traffic. However, there are general signs that can help you spot a DDoS attack on your organization:

• Sudden sluggishness or unresponsiveness of your website or service
• Frequent crashes of a server or application
• Rapid spikes in bandwidth usage
• Increased traffic from unexpected IP addresses
• High numbers of specific types of requests (like HTTP or DNS queries)

Monitoring your traffic in real time, establishing network baselines, and leveraging automated traffic alerts can help you recognize these deviations and detect DDoS attacks early on.

In the event of an attack, the following DDoS mitigation techniques will help you stop an assault or reduce its impact on your organization:

• Filter malicious traffic. Some intrusion prevention systems and advanced firewalls can help you block part of the attack by filtering out traffic from suspicious or malicious IP addresses.
• Set rate limitations. Thresholding your traffic rates can help you reduce the amount of malicious traffic flowing through your network while keeping services available to real users.
• Turn on backup servers. If you have spare servers, use them to distribute the load of a DDoS attack and reduce downtime.
• Apply black hole routing. Creating a black hole route and streaming all traffic into that black hole may seem extreme, as it absorbs legitimate traffic as well. In some cases, however, it can prevent your service from crashing.
• Use dedicated software. Anti-DDoS software and services specialize in mitigating these types of attacks, helping you detect and block malicious traffic effectively.

To maximize the effectiveness of your DDoS protection efforts, it’s vital to support them with other cybersecurity tools, processes, and services to help you fight other cyber threats.

Consider implementing Syteca – a comprehensive cybersecurity platform. Syteca helps you secure your organization’s inside perimeter by monitoring user activity in real time, proactively managing employee access, and automatically responding to security events.