What are DDoS Attacks and How to Avoid Them?

DDoS attacks can be brief or repeated, with an impact on your website that can last for days, weeks, or even months. See how to protect yourself here.

What are DDOS Attacks and How to Avoid Them?

DDoS attacks are increasing by 31% year over year. Unlike other types of cyberattacks, DDoS attacks do not attempt to breach your security perimeter or steal data. They aim to make your website and servers unavailable. They can also serve as a smokescreen for other malicious activities.

DDoS attacks can be brief or repeated, with an impact on your website that can last for days, weeks, or even months. 

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DDoS attack, an invasion of “zombies”

DDoS is short for Distributed Denial of Service. This attack seeks to disrupt a website or network by flooding it with traffic.

To better understand how it works, imagine waiting for a call from a friend. Suddenly, thousands of numbers start calling you simultaneously for no reason. The chances of receiving your friend's call are considerably reduced. In addition, your telephone line will be completely saturated and unusable during this time.

A DDoS attack infiltrates a web server to send so many requests to serve a page that it collapses under demand. As a result, available Internet bandwidth, CPU, and RAM capacity will be exceeded. 

The impact can range from minor inconvenience due to disruption of services to bringing websites, apps, or even entire businesses offline.

Denial of service attacks uses malware to create a botnet, which can be considered an army of "zombie" computers. This army is sent to the front, in a network, to attack a website or an online service.

In many cases, a "zombie" PC owner is unaware of the malware infection. He is a victim of the script that will launch the DDoS attack.

DDoS attack categories

There are several types of DDoS attacks classified into 3 main categories:

1. Volume-based attacks

Volume-based DDoS attacks remain the most common. Hackers use a large number of computers and Internet connections (often spread all over the world) to flood a website with traffic. The goal? Obstruct available bandwidth.

Legitimate traffic can't get through, and the hackers manage to take the site down. An example of a volume-based attack is User Datagram Protocol (UDP) flooding. The hacker sends packets of information and protocols unknown to the network to destabilize it and bring it down.

2. Protocol attacks

Unlike volume-based attacks, protocol attacks aim to exhaust server resources rather than bandwidth. They specifically target the intermediaries between the server and the website, such as firewalls and load balancers.

Hackers overwhelm web pages and resources by making fake protocol requests to consume all available resources.

An example of this type of attack is the Smurf DDoS or rebound attack. The targeted network responds to attacks by targeting itself, which increases its overhead.

3. L7 or application attacks

L7 attacks require fewer resources than the previous two while being the most sophisticated. They target vulnerabilities within applications (hence their name) such as Apache, Windows, and OpenBSD.

They bring down servers by making a large number of requests that seem legitimate at first glance by mimicking user traffic behavior. 

L7 attacks seek to disrupt specific functions or features of a website, such as online transactions. However, unlike other attacks, they can go unnoticed.

DDoS attacks are evolving every day. A new trend is that of "mixed attacks." Hackers launch a protocol attack to create a distraction, then an L7 attack. These types of threats are increasingly frequent, complex, and sometimes difficult to combat.

How do you know if you are under a DDoS attack?

A denial of service attack generates a lot of traffic to your site, which creates an awkward situation. How do you know if your site is doing well or if you are currently undergoing a maneuver from hackers?

Check where your traffic is coming from to get started. If you observe a sudden increase in the number of visitors, look for the cause: a marketing campaign, the quote of your company on television, a promotional email, the publication of a post on social networks (by your brand or an influencer), etc.

In the event that no marketing action is underway to explain this sudden increase, wait a few minutes. If an outage occurs due to a spike in legitimate traffic, it is usually only a matter of seconds before the site is back up and running.

Finally, to fully answer the question of how to know if you are under a DDoS attack, be aware that several clues should alert you:

  • The website is unavailable for several minutes for no apparent reason.
  • Accessing the website takes a long time.
  • The same IP address makes a lot of requests in a few seconds.
  • Your server is responding with a 503 error due to a service outage.
  • The TTL (time to live) of a ping request is exceeded.
  • You notice slowness issues with other internal tools connected to the same network as your website.

How to counter a DDoS attack?

In cybersecurity, prevention is always better than cure. This is even more true in the case of DDoS attacks. You don't want to see your site inaccessible for hours or days. You risk losing revenue.

So how do you counter a DDoS attack? Here are some best practices to adopt now:

  • Implement DDoS attack prevention solutions

Equip your network, applications, and IT infrastructure with multi-layered protection strategies. This can be prevention management systems that combine firewalls, VPNs, anti-spam, content filtering, and other layers of security.

Their goal will be to monitor activity and identify traffic inconsistencies that are symptoms of DDoS attacks.

  • Use a Content Delivery Network (CDN)

A modern and effective way to deal with denial of service attacks is to use a Content Delivery Network (CDN). Since DDoS attacks work by overloading a server, CDNs can help by sharing the load evenly across several servers, geographically distributed and closer to users.

Thus, if a server fails, others remain operational and take over.

  • Assess the vulnerability of your network

With the help of your IT manager, identify the weaknesses in your networks so that you can reinforce the vulnerabilities and counter a DDoS attack before it takes place.

To do this, it is necessary to take an inventory of all the devices present on the network. This is an opportunity to identify those that are obsolete or useless in order to delete them. 

Regarding those to keep, specify their function, system information, and any vulnerabilities associated with them. The corrective measures will appear to you by themselves.

This vulnerability audit of your network must be carried out regularly to best anticipate all cybersecurity threats.

  • Move to the cloud

There are several advantages to migrating your data to the cloud. Cloud providers offer high levels of cybersecurity, including firewalls and threat monitoring software. Which can help protect your assets and network from DDoS attacks. Additionally, vendors provide network redundancy, duplicating copies of your data, systems, and equipment.

If your service is corrupted or unavailable due to a DDoS attack, you still have backed-up versions of your website, application, and tools.

How to block a DDoS attack?

A DDoS attack can cause your website to go down, your search engine rankings to drop, and your data to be lost. Even with protective measures, risk 0 does not exist.

Here's how to block a DDoS attack:

  • Overbudget bandwidth

One of the quick ways to stop a DDoS attack is to expand your bandwidth as soon as you notice a sudden, inexplicable increase in the volume of traffic to your site.

Most web hosts allow you to quickly expand your bandwidth and support an additional spike in traffic. This will buy you time to find the attack's origin and counter it completely.

  • Protect your network perimeter

In the first minutes after a DDoS attack, a few technical measures will help you mitigate the effects. For example, you can:

  • Limit your router's speed to prevent your web server from being overwhelmed.
  • Add filters to tell your router to drop packets from obvious attack sources.
  • Delay half-open connections more aggressively.
  • Drop spoofed or malformed packets.
  • Set lower thresholds for eliminating SYN, ICMP, and UDP floods.

  • Contact your host

Depending on the strength of the DDoS attack, the hosting company may have already detected it, or they may even be the target.

Their data center probably has larger bandwidths and higher capacity routers than your company's. Their staff might also have experience in dealing with cyber threats. So do not hesitate to contact them as soon as the attack begins.

The host can "route block" your traffic to prevent packets from reaching your site.


After a DDoS attack, analyze your logs to identify the targeted services and assess the damage and the patterns used. This will allow you to recognize your weak points to strengthen your protection. 

File a complaint at the police station if there has been theft of personal data.

To counter and block DDoS attacks before they occur, engage the services of a cybersecurity expert. It can help you secure your computer network and website as much as possible.

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