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What is a Distributed Denial-of-Service (DDoS) Attack and How Do You Deal With It?

6 min read

By George Drennan

When you hear about a website being “brought down” by hackers, a distributed denial-of-service (DDoS) attack is usually the culprit.

If you’re the target of a DDoS attack, the damage to your business goes beyond the loss of revenue while your customers can’t access your website. It can take years to rebuild trust with your customers and repair your reputation.

In this guide, we’ll examine what a DDoS attack is and what you can do to get your website back online.

What Is a DDoS Attack?

A distributed denial-of-service attack is a type of cyberattack used to disrupt the availability of a website to end-users. A hacker uses malware to control multiple compromised devices and flood the target website with requests. Ultimately, this overwhelms the server, and the website becomes inaccessible.

This type of cyberattack is becoming increasingly common. The number of DDoS attacks worldwide is expected to exceed 15.4 million annually in 2023, up from 7.9 million in 2018.

The first noticeable sign of an attack is that the website suddenly becomes much slower or is unavailable to users. However, there could be a legitimate cause behind a spike in traffic that causes these performance issues.

One of the biggest challenges in identifying and repelling a DDoS attack is that it can be difficult to separate legitimate website traffic from compromised attack traffic.


How To Mitigate a DDoS Attack

Prevention is often the best form of defence, so we’ll discuss how to protect your website from a DDoS attack and what to do in the event of one.

1. Know What a DDoS Attack Looks Like

The faster you recognize a DDoS attack, the quicker you can mitigate the effects and get your website back online.

You should familiarize yourself with your average website traffic profile. If you know what your average number of visitors looks like, you can spot an unusual spike that could be a sign of a DDoS attack.

Analyzing your traffic in more depth may reveal that lots of traffic is coming from a single IP range – indicating that the traffic may be artificial. The same goes for large amounts of traffic that share the same geolocation or device type.

If you are receiving lots of requests for a single page on your site, that could indicate that the traffic is not natural.

You can also look for patterns to see if anything looks unusual. For example, if you experience large spikes in traffic at regular intervals, it could indicate that a DDoS attack is ramping up.

DDOS AttackShutterstock

2. Defend at the Network Perimeter

Once you have confirmed your website is being targeted, there are several ways you can slow down the attack.

The first measure is to rate-limit your router. You can assign a bandwidth restriction to specific connection types or categories of traffic to stop your server from being overwhelmed.

You can also add filters that tell your router to drop packets from sources of the attack and implement a more aggressive timeout for half-open connections.

The challenge with a DDoS attack is that traffic usually comes from an extensive range of IP addresses. It can be difficult to determine which IPs are legitimate and which are part of the attack.

These tactics can prevent your website from being brought down, but DDoS attacks are getting more sophisticated. The above measures may buy you some time, but they are unlikely to stop a DDoS attack entirely.

Changing internet router settingsShutterstock

3. Contact Your ISP or Hosting Provider

Your next option is to contact your ISP or hosting provider and inform them of the attack.

If you use a hosting provider, your corporate network will be separate from your website server. This means you will still be able to use your company email, VoIP phones, and other services that use your LAN.

You may find that your ISP or hosting provider has already detected the DDoS and started to implement mitigation measures.

This usually involves “blackhole filtering.” The packets being sent to your web server are dropped rather than being forwarded to your website.

Blackhole filtering acts as a basic firewall that keeps all traffic from reaching your server. Unfortunately, this means legitimate traffic will also be dropped, and real visitors will be unable to access your website.


4. Traffic Scrubbing

The vast majority – over 97 percent – of DDoS attacks last for less than an hour:

If your website is under sustained attack, your next option is to engage an internet security company that offers a traffic scrubbing service.

Traffic scrubbing works by intercepting the traffic trying to access your website and filtering out malicious packets. As a result, legitimate traffic is forwarded to your website, and malicious traffic is blackholed.

There is an impact on performance for end-users, but the alternative is that your website would be completely inaccessible due to the server being overwhelmed.

Traffic scrubbing services can be expensive. It will depend on the size and duration of the attack as to whether it is worth engaging an internet security specialist.

Success: In 2018, GitHub was the target of one of the biggest ever DDoS attacks. However, the company had a documented playbook on how to deal with a DDoS attack and quickly sounded the alarm to its cybersecurity partner Akamai Prolexic. By using traffic scrubbing, Akamai Prolexic was able to get the GitHub website back online within 20 minutes.

5. Use a Content Delivery Network

When you use a CDN, your website files are cached on multiple servers around the world. This means that your website visitors can access the website files on the server closest to their location, and loading time is significantly reduced.

A CDN can also help to protect your website from a DDoS attack.

Because the CDN redistributes your website traffic to multiple servers, it can prevent malicious packets from reaching your origin server and bringing down your website. Instead, the cached version of your website is used, and your origin server is left untouched.

In many cases, the capacity of the CDN network is enough to handle the size of the DDoS attack. CDN providers usually offer additional security features to help mitigate DDoS attacks, including network perimeter protection.

It’s still possible for a DDoS attack to reach your server, but a CDN does offer an extra layer of protection.


6. Be Aware of Secondary Attacks

A DDoS attack is often used as a distraction tactic for an even more damaging cyberattack. While your attention is focused on mitigating the DDoS and getting your website back online, a hacker can access your server.

According to a survey by internet security company Kaspersky, 56 percent of companies that have been the target of a cybercrime believe that a DDoS attack was used as a smokescreen for other criminal activities.

It’s important to see the bigger picture and make sure there are protections in place to mitigate data theft and other nefarious activities that could be performed during a DDoS attack.


7. Create A DDoS Response Plan

Like any other risk to your business, you should have documented protocols on how to respond if you are hit with a DDoS attack. Staff should be trained on how to respond when a DDoS attack is detected.

Make sure all contact information for ISPs and hosting providers are readily accessible and up to date. If you have a contract with an internet security service provider, make sure their contact information is available to staff.


8. Test Your Response With a DDoS Simulation

Once you have drafted a playbook, consider running a simulation DDoS attack to test your strategy and identify ways you can improve your response.

You’ll need to inform your ISP or hosting provider of the DDoS simulation and make sure it doesn’t breach the terms of your contract. In addition, some companies require you to use approved DDoS testing partners.


Protecting Your Website From a DDoS Attack

Cybersecurity should be a priority for your business. If you don’t prepare and put protections in place, you leave yourself vulnerable to hackers.

Using the above steps, you can protect your server, stop an attack, and quickly get your website back online.

About the Author

Subject Matter Expert

George Drennan is the founder of Eagle Content, a UK-based copywriting company, and a writer on all things business and tech. A graduate of University College Falmouth, he believes that everyone should be able to access the best information to make the right decisions for their business and future.

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