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  • Writer's pictureNexix Security Labs

What is a DDoS attack and how does it work?

DDoS Attack_NSL

Recent years have seen a steady rise in Distributed Denial of Service (DDoS) assaults in the IT sector. DDoS attacks were once thought of as minor inconveniences committed by inexperienced attackers for fun, and they were quite simple to mitigate. Sadly, such circumstances are no longer present.

In recent years, DDoS attacks have increased exponentially have rendered firms largely inoperable.

  • In February 2020, Amazon Web Services (AWS) experienced a DDoS attack that was so sophisticated that it kept its incident response teams busy for days while also having an impact on customers all around the world.

  • The EXMO cryptocurrency exchange was the target of a DDoS attack in February 2021, which kept it inaccessible for about five hours.

  • Australia recently suffered from a significant, ongoing, state-sponsored DDoS onslaught.

  • A DDoS attack that targeted the government, police, and universities of Belgium also made Belgium a victim.

Every day, tens of thousands of successful DDoS attacks go unreported and nameless. In actuality, the most successful and expensive attacks are these ones. Because of the predicted growth of DDoS, IT professionals with expertise in mitigation are in great demand.

What is a DDoS attack?

DDoS is an abbreviation for Distributed denial of service. When a threat actor targets an organization's online activities using resources from numerous, distant places, the attack is known as a DDoS. DDoS assaults often concentrate on producing attacks that interfere with network services and equipment's normal operations (e.g., routers, naming services or caching services). In actuality, that is the fundamental issue.

It's not necessary for sophisticated DDoS attacks to take advantage of open relays or default settings. They take advantage of expected behavior and the original design of the protocols that are used by modern devices. A DDoS attacker manipulates the typical operation of the network services that we all depend on and trust in a similar manner to how a social engineer manipulates the default workings of human communication.

A DDoS attack overwhelms the targeted organization's resources with HTTP requests and traffic, preventing genuine users from accessing one or more of its services, resulting in a devastating outage. DDoS attacks, along with supply chain attacks, ransomware, and social engineering, are among the top four cybersecurity concerns of our day.

Types of DDoS attacks

  1. Application Layer

Attack on the application layer target the software that actually offers a service, such as the widely used web server Apache Server or any application made available by a CLOUD PROVIDER. In recognition of the matching number of the application layer in the OSI/RM, this is the most prevalent type of DDoS assault and is frequently referred to as Layer 7 attacks.

2. Protocol

When an attack uses up the resources of crucial servers and network-based devices, like firewalls or the operating system of a server, this happens. Balancers are loaded while such resources are overloaded. Layer 3 and Layer 4 of the OSI/RM traffic manipulation is a common component of protocol assaults (the network and transport layers, respectively). This is the second most typical DDoS attack type.

3. Volumetric

Attacks using a large amount of DDoS are typically launched against a specific target, usually enterprise clients or critical Service Provider (SP) services.

Identifying DDoS attacks

One of the most important abilities you need to possess for tactical DDoS mitigation is pattern recognition. It's crucial to recognize patterns that indicate a DDoS attack is happening, especially in the early going. In order to distinguish between legal traffic and a DDoS assault, businesses frequently use automated apps and AI as assistants.

Workers frequently search for the following warning signs indicating a DDoS attack is occurring:

  • Reports from existing mitigation devices (e.g., load balancers, cloud-based services)

  • Customers report slow or unavailable service

  • Employees utilizing the same connection also experience issues with speed

  • Multiple connection requests come in from a specific IP address over a short amount of time

  • You receive a 503 service unavailable error when no maintenance is being performed

  • Ping requests to technology resources time out due to Time to Live (TTL) timeouts

  • Logs show an abnormally huge spike in traffic

Step for DDoS attack response

Typical steps for responding to a DDoS attack include:

1. Detection

An effective DDoS defense depends on early detection. Watch out for the warning indicators that you might be a target that are listed above. Layer 7 and protocol-based attacks can be found by looking at the content of packets, while volumetric attacks can be found by using rate-based metrics. When it comes to DDoS attacks, rate-based detection is frequently brought up first, although the majority of DDoS attacks are not stopped by this method.

2. Filtering

Unwanted traffic can be reduced with the use of a transparent filtering mechanism. This is accomplished by setting up efficient policies on network hardware to stop DDoS traffic.

3. Diversion and redirection

This stage entails redirecting traffic to protect your vital resources. DDoS traffic can be redirected by being directed into a sinkhole resource, such as a scrubbing centre. It is usually advised that you openly explain what is happening so that workers and consumers won't need to adjust their behavior to account for slowness.

4. Forwarding and analysis

It's crucial to know where the DDoS attack started. You can create protocols to proactively defend against assaults using this knowledge. Although it may be tempting to try and destroy the botnet, doing so can cause practical issues and could have legal repercussions. It is typically not advised.

5. Alternate delivery

In the event of an attack, it is feasible to employ other resources that can nearly immediately deliver new material or establish new networking connections.

Responding as a team and working together during the incident response process is one of the best strategies to lessen the impact of a DDoS assault. The aforementioned steps can only be completed by a collaboration of people, services, and gadgets. For instance, it is frequently important to take the following actions to reduce Layer 7 DDoS attacks:

  • Detection: To discover Layer 7 attack patterns, organizations will combine security analyst and penetration testing activities. The DDoS assault is typically simulated by a penetration tester, and the security analyst attentively listens to hear any unusual characteristics.

  • Traffic filtering: To assist in rerouting and containing hazardous traffic, use scrubbing facilities and services.

  • Layer 7 control: It is frequently possible to tell whether a network connection request comes from a human or a bot by using CAPTCHAs and cookie challenges.

  • Forwarding of packets to a security professional for further analysis: Pattern recognition exercises will be used by a security analyst, who will then suggest mitigating action based on their findings.

  • Alternate delivery during a Layer 7 attack: When your resources are defending against the attack, using a CDN (content delivery network) could support more uptime. It is significant to remember that mitigating tools can malfunction. It might not be updated or configured correctly, and it might even contribute to the issue during a DDoS attack.

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