Key Takeaways
- DDoS attacks overwhelm servers, networks, or applications with traffic from multiple sources, disrupting services and preventing legitimate users from accessing them.
- Common DDoS attack types include volumetric attacks, protocol attacks, and application layer attacks, each targeting different network or system resources.
- Warning signs of a DDoS attack include unusual traffic spikes, slow network performance, service unavailability, and increased failed requests.
- Layered defenses such as traffic filtering, rate limiting, load balancing, and dedicated DDoS mitigation services help reduce attack impact and maintain service availability.
- Fidelis Elevate® supports network visibility, threat detection, investigation, and forensic analysis, complementing dedicated DDoS protection services.
What is a DDoS Attack?
A Distributed Denial of Service (DDoS) attack is a cyberattack that attempts to disrupt the normal functioning of a server, service, or network by overwhelming it with traffic from multiple sources. To understand what a distributed denial of service attack is, it is important to know that attackers often use a network of compromised devices, known as a botnet, to send excessive requests or packets to a target. This can exhaust bandwidth, processing power, or other system resources, slowing down services or making them unavailable to legitimate users. DDoS attacks can affect websites, applications, online services, and business networks, leading to downtime and operational disruption.
How do DDoS Attacks Work?
Understanding how a distributed denial of service attack works helps organizations recognize malicious traffic patterns and reduce service disruptions. These attacks typically involve compromised devices sending coordinated traffic toward a target, exhausting its resources and preventing legitimate users from accessing the service.
1. Compromise Multiple Devices
The initial phase of a DDoS attack involves assembling what is known as a botnet. A botnet is a group of compromised devices controlled by an attacker. Attackers may compromise thousands of devices by exploiting vulnerabilities or using malware to gain control. These devices can include computers, IoT devices, routers, and security cameras.
2. Botnet Command and Control
The botnet is under the attacker’s influence from a command-and-control (C&C) server. The attacker makes use of the C&C server to interact and convey instructions to launch an attack.
3. Flooding Target with Traffic
Once the attacker is ready, they instruct the botnet to flood a server, network, or application with traffic. Depending on the attack method, this traffic may consist of HTTP requests, UDP packets, or other network traffic. The resulting influx can overwhelm the target’s available resources and disrupt legitimate access.
3. Resource Exhaustion
As traffic increases, the target may exhaust its available bandwidth, connection capacity, CPU, or memory. As a result, it may struggle to process legitimate requests, leading to slow response times, errors, or a complete denial of service.
4. Disruption of Services
Users are commonly unable to reach the affected service as long as the DDoS attack continues. It can run for hours, days, and in certain situations for weeks depending on the power of a botnet and determination of an attacker.
- What data has been potentially exposed?
- Incursion detection and Persistence detection
- How should I respond?
What are the most common types of DDoS attacks?
DDoS attacks are broadly divided into three categories.
1. Volumetric Attacks
Volumetric DDoS attacks aim to overwhelm a target with large volumes of traffic, saturating available network bandwidth and preventing legitimate requests from getting through. Attack magnitude is typically measured in bits per second (bps). Common methods include UDP floods and ICMP floods. Attackers may also use reflection and amplification techniques to increase the volume of traffic directed at a target.
2. Protocol Attacks
Protocol attacks target weaknesses in network protocols or exhaust the connection-handling capacity of network infrastructure, such as firewalls, routers, and load balancers. These attacks typically operate at Layers 3 and 4 of the OSI model and are commonly measured in packets per second (pps). Examples include SYN floods and Ping of Death attacks. DNS amplification is a reflection and amplification technique that can also contribute to network-level disruption.
3. Application Layer Attacks
Application layer DDoS attacks, also known as Layer 7 attacks, target specific applications and services, such as web servers. HTTP floods and Slowloris attacks are common examples. They attempt to exhaust application resources by generating excessive requests or keeping connections open for extended periods. Although these attacks may use less traffic than volumetric attacks, they can still disrupt services by consuming server resources. Attack activity is often measured in requests per second (rps). SQL injection is a separate application-layer attack and should not be classified as a DDoS attack.
Common methods used in DDoS attacks include UDP floods, SYN floods, ICMP floods, HTTP floods, and DNS amplification attacks. While UDP and ICMP floods generate large volumes of packets, SYN floods target TCP connection handling, and HTTP floods overwhelm web applications with excessive requests. DNS amplification uses reflection techniques to direct amplified traffic toward a target. Attackers may combine multiple methods to disrupt network infrastructure and applications simultaneously.
Impact of DDoS Attacks on Businesses
Understanding what is a distributed denial of service (DDoS) attack is not enough, businesses also need to realize its implications. Some of those impacts are:
- Revenue loss: DDoS attacks can break down the network or business websites which may cause substantial revenue loss. The businesses that wholly operate online (ecommerce, SaaS providers, other online services) may incur loss for every downtime second. Also, it impacts operations, disrupts workflow and delays the projects. This can also be included as a hidden cost from the company.
- Brand reputation damage: As DDoS attacks directly hit the availability of services, lack of services and fear of breach of data may impact the brand reputation of the company and can increase customer attrition. These attacks, similar to famous DDoS attacks that received widespread coverage, often act as negative PR and attract unnecessary media attention. The impact of major DDoS attacks can be long-lasting and will require efforts to reinstate the reputation.
- Increased security and recovery costs: A company has to bear hefty costs to reiterate the services and mitigate threats. Specialized security services would also be required to dilute the attack and prevent potential future threats.
- Breach of customer trust: Distributed denial of service attack creates fear mongering within the customers and creates a negative impact on customer’s trust. A company may also lose its loyal customers, and may lead to decreased customer retention.
How to Identify a DDoS Attack
Recognizing what is a DDoS attack in action can prevent extended downtime. One of the biggest indicators of a Distributed denial of service attack is extremely slow network performance. DDoS (Distributed Denial of Service) floods the network with malicious traffic to overwhelm the server crippling service for legitimate users. Page loads can take longer, responses might lag, or it could time out when trying to establish a connection.
Another set of signs of a DDoS attack is the unavailability or error of services that are typically accessible. If your site or other service suddenly becomes unreachable or developers get random error messages, this is indicative of a DDoS attack. Server performance monitoring tools can notify you when unusual spikes in traffic occur and will send alerts if there is a considerable, sudden increase in failed requests.
Spikes in traffic from a single IP address or geographic location, especially if they deviate from regular usage patterns, also suggest a possible attack. Being able to identify these red flags at an early stage enables IT teams to respond faster, which means reduced downtime and ensured service continuity.
How Do DDoS Attack Statistics Vary Across Different Regions?
DDoS attack trends vary across regions depending on internet infrastructure, industry concentration, the availability of compromised devices, and attackers’ objectives. Some regions may experience more attacks targeting cloud infrastructure, financial services, telecommunications, and government networks, while others may see different patterns based on their digital ecosystems.
Regional comparisons can consider attack frequency, duration, traffic volume, packet rates, and the industries most frequently targeted. However, the results depend on the reporting period, the security provider’s network visibility, and the metrics used. Organizations should consult recent DDoS threat intelligence reports to understand regional trends and assess how these patterns may affect their infrastructure and security priorities.
Defending Against DDoS Attacks
To understand how to combat DDoS attacks, organizations need a layered protection model to reduce impact and provide active network resilience. Some of the same strategies for defending against DDoS attack:
- Traffic Filtering: Firewalls and network-level IP filtering are some of the most basic types of defenses a firewall might offer. These tools help reduce the impact of an attack by filtering out malicious traffic before it reaches sensitive network components. It is based on detecting anomaly patterns against IP addresses.
- Rate Limiting: It offers a way to limit requests per second going in so that it does not overload. Simple rate limiting will restrict the requests and still lower the risk of service downtime.
- Load Balancing: Load balancing distributes the traffic to multiple servers so that no single server gets overloaded. It distributes the traffic for effective load balancing, and also ensures that service will be available during events of high traffic on website, server, or application.
- DDoS Mitigation Services: Third-party DDoS mitigation services are designed with rich features to detect and filter all potential attacks on the move. Such services will analyze traffic, perform filtering techniques, or even clean up and redirect malicious traffic away from the network so that the effect of the attack is minimal.
How Fidelis Elevate® Supports Network Threat Detection and Response
Fidelis Elevate® is an extended detection and response (XDR) platform that provides integrated visibility and threat analysis across networks, endpoints, and cloud environments. Its network analytics, threat intelligence, and forensic capabilities help security teams identify suspicious activity, investigate potential threats, and respond to security incidents.
- Network Visibility and Threat Detection: Integrated Fidelis Network® provides network visibility and traffic analysis to help security teams identify anomalous behavior and investigate suspicious activity. This visibility can support the investigation of unusual network traffic patterns that may warrant further examination during a suspected DDoS incident.
- Threat Investigation and Response: Fidelis Elevate supports threat detection and response workflows, helping security teams analyze suspicious activity, correlate relevant security information, and investigate potential threats. These capabilities can help teams understand the broader security context surrounding network disruptions.
- Network Forensics: Fidelis provides network forensic capabilities that help security teams examine traffic, analyze suspicious communications, and reconstruct activity associated with potential security incidents. This information can support post-incident investigations and help organizations strengthen their security controls.
For direct DDoS prevention and mitigation, organizations should also consider dedicated DDoS protection services that can filter malicious traffic, absorb attack traffic, and help maintain service availability. Fidelis Elevate can complement an organization’s broader security operations by providing visibility and investigation capabilities across its environment.
- Network, Cloud, and Endpoint Security
- 9x Faster Detection and Response
- Full Control of Your Attack Surface
Conclusion
DDoS attacks remain a significant threat to businesses, potentially disrupting services, causing financial losses, and damaging customer trust. Understanding how these attacks work, recognizing their common types and warning signs, and implementing layered defenses can help organizations reduce their impact and maintain service availability. Traffic filtering, rate limiting, load balancing, and dedicated DDoS mitigation services play important roles in protecting critical infrastructure.
In addition, platforms such as Fidelis Elevate® support broader security operations through network visibility, threat detection, and forensic investigation. Combining dedicated DDoS protection with continuous security monitoring and incident response helps organizations strengthen their resilience against evolving cyber threats.
Frequently Asked Questions
What is a DDoS attack and how does it work?
A DDoS (Distributed Denial of Service) attack is when multiple compromised devices, known as a botnet, flood a server or network with excessive traffic. This overloads bandwidth or system resources, making the service unavailable to legitimate users.
What is the difference between DDoS attack vs DoS attack?
A DoS attack typically originates from a single source or system, where the attacker sends an overwhelming volume of requests to the target, causing the service to slow down or crash. These attacks are relatively simpler to execute and, because they stem from one location, can often be blocked by identifying and filtering the attacker’s IP address.
On the other hand, a DDoS attack is significantly harder to execute and powerful, as it employs thousands of compromised devices (also known as “botnet”) finding floods traffic from various locations against the target. This dispersed approach makes it almost impossible to deal with DDoS attacks. Changing IPs, request types, and locations can allow them to bypass traditional security defenses which poses a major problem for network administrators who need their services available at all times while still capable of defending against such attacks.
What is the primary goal of a DDoS attack?
The main purpose of a DDoS attack is to flood a specific server / network with so many requests with high traffic causing it unable to handle and eventually stopping the access for genuine users over the service/application. By exhausting system resources, attackers can create downtime, impact revenue, and damage the reputation of the targeted organization.
What is the most common form of a DDoS attack?
The basic type of DDoS attack is the Volumetric Attack, which sends a flood of data to an entire network, exhausting the bandwidth. This includes techniques such as UDP floods and ICMP floods, which overload the server and disable regular traffic.
How long can DDoS attacks last?
DDoS attacks can vary in duration — lasting anywhere from a few minutes to several weeks, depending on the goal of the attacker and the scale of the attack, as seen in some of the largest DDoS attacks recorded. However, persistent attacks — including some of the biggest DDoS attacks — are often more difficult to mitigate and will last for hours and even days (which can be harmful to businesses when services need restoration).
