What Is DDoS Mitigation? Protecting Your Network

Distributed Denial-of-Service (DDoS) attacks are a type of cyberattack that target specific applications or websites with the goal of exhausting the target system’s resources, rendering it unreachable or inaccessible to legitimate users. In 2023, application layer attacks are up by 165%, with the technology sector taking the top spot as the most attacked of all verticals. This is why having a comprehensive DDoS mitigation solution in place is critical to maintain uptime and resiliency.

Key Concepts in DDoS Attacks

Before diving into DDoS mitigation methods and solutions, it’s important to get a deep understanding of today’s DDoS threats. A distributed denial-of-service (DDoS) attack degrades infrastructure by flooding the target resource with traffic, overloading it to the point of inoperability. A DDoS attack may also send a specifically crafted message that impairs application performance. DDoS attacks can target network infrastructure such as firewall state tables, as well as application resources such as servers and CPUs.

DDoS attacks can have severe consequences, compromising the availability and integrity of online services and causing significant disruption, with the potential for financial losses and reputational damage. These attacks can also be used as a distraction so that bad actors can access important data. 

DDoS attacks are a type of Denial of Service (DoS) attacks, which seek to disrupt the normal functioning of a network, server, or website by overwhelming it with traffic. On the other hand, a DDoS attack uses multiple devices to flood the target with traffic. Because a DDoS attack involves several systems attacking a single system, they represent a far bigger threat, and one that is more complicated to thwart.

These are the common types of DDoS attacks seen in the seven-layer Open Systems Interconnection (OSI) model:

Volumetric attacks are designed to overwhelm a network with such a huge volume of traffic that the network becomes inoperable. These attacks are typically executed using a botnet, which is a network of compromised devices that are controlled by a single attacker.
Protocol attacks target the network layer of the OSI model and exploit vulnerabilities in network protocols such as TCP/IP, ICMP, and UDP. These attacks are designed to overload the resources of network devices such as firewalls, routers, and load balancers, thereby causing service disruption. These are also known as “computational” attacks.
Application layer attacks target the application layer of the OSI model and exploit vulnerabilities in web applications such as HTTP, HTTPS, and DNS. These attacks are designed to exhaust the resources of web servers, thereby causing service disruption.

Common attack vectors used in DDoS attacks:

UDP flood: This attack floods the target server with User Datagram Protocol (UDP) packets, which can cause the server to crash or become unresponsive.
TCP SYN flood: This attack exploits the three-way handshake process used by the Transmission Control Protocol (TCP) to establish a connection between two devices. The attacker sends a large number of SYN packets to the target server, which can cause it to become unresponsive.
HTTP flood: This attack targets web servers by sending a large number of HTTP requests to the target server, which can cause it to become unresponsive.
DNS amplification: This attack exploits the Domain Name System (DNS) to flood the target server with DNS response packets, which can cause it to become unresponsive.
NTP amplification: This attack exploits the Network Time Protocol (NTP) to flood the target server with NTP response packets, which can cause it to become unresponsive.
SSDP amplification: This attack exploits the Simple Service Discovery Protocol (SSDP) to flood the target server with SSDP response packets, which can cause it to become unresponsive.
SYN-ACK flood: This attack exploits the TCP three-way handshake process by sending a large number of SYN-ACK packets to the target server, which can cause it to become unresponsive.
HTTP slow read: This attack sends HTTP requests to the target server but reads the response slowly, which can cause the server to become unresponsive.
Ping of death: This attack sends an oversized ping packet to the target server, which can cause it to crash or become unresponsive.
Smurf attack: This attack exploits the Internet Control Message Protocol (ICMP) to flood the target server with ping requests from multiple sources, which can cause it to become unresponsive.
Heavy URL: During the reconnaissance phase of attack planning, an attacker searches for a website’s most computationally expensive URLs and uses them as part of a DDoS attack. These are known as “heavy” URLs because they place greater load on the server when requested.
Low and slow: The goal of these DDoS attacks is to bring application resources down quietly and stealthily—and do it using very little bandwidth. Because of that, they’re hard to detect, and because they occur at the application layer where a TCP connection is already established, the HTTP requests appear legitimate.

So the threat from DDoS attacks is enormous, potentially leaving companies more vulnerable to cyberattacks. That means it is essential to understand how DDoS attacks happen, so that you can take steps to mitigate them.

Why It’s Critical to Implement DDoS Mitigation in a Cybersecurity Policy Availability:

DDoS attacks can cause significant downtime and disrupt the availability of services, leading to financial losses and reputational damage.

Protection: By incorporating DDoS mitigation measures, your company reduces the risk of malicious traffic reaching their network infrastructure, while ensuring legitimate users can access their websites and web applications. DDoS attacks are sometimes used as a smokescreen to distract security teams from a coordinated attack campaign that can lead to data breach. And some types of attacks simply cannot be “coded” away.

Resilience: Investing in effective DDoS mitigation technology enhances an organization’s resiliency against nation-state adversaries and other malicious actors, making it a less attractive target.

Cost savings: Rapidly mitigating DDoS attacks can save organizations time and money.

By including DDoS mitigation in a cybersecurity policy, organizations can proactively protect their resources, maintain service availability, and minimize the impact of potential DDoS attacks.

DDoS Mitigation Techniques

Now we understand what is at risk in being vulnerable to DDoS attacks, including business-critical data and applications, and why it’s critical to deploy a DDoS mitigation solution. We can now review the types of DDoS mitigation so that you can determine the best solution for your needs.

On-Premises DDoS Mitigation

There are several types of on-premises solutions and measures that an organization can implement to reduce the risk of DDoS attacks. Some of these may also be used in addition to cloud-based ones to build a stronger overall defense posture.

Network infrastructure strengthening: This solution involves reinforcing the network infrastructure to withstand DDoS attacks. It includes increasing bandwidth, adding redundant links, and upgrading network devices.
Rate limiting and traffic shaping: This solution involves limiting the amount of traffic that can enter the network. It can be implemented by setting up rate limits on the network devices or by using traffic shaping techniques to prioritize traffic.
Firewalls and intrusion prevention systems (IPS): This solution involves using firewalls and IPS devices to filter out malicious traffic. Firewalls can block traffic based on IP addresses, ports, and protocols, while IPS devices can detect and block attacks based on their signatures.

Cloud-Based DDoS Mitigation

Moving DDoS mitigation efforts to the cloud or a hybrid solution helps increase efficiency, scalability, and efficacy. Some cloud-based solutions can be integrated with on-premises solutions. Cloud-based DDoS mitigation solutions operate on cloud-delivery networks, or CDNs.

Anycast routing distributes traffic to the nearest data center that can handle it. It works by announcing the same network in different parts of the network, to reduce the network “travel time” to get to that network. When a CDN network uses anycast routing, it distributes traffic more strategically, which increases the surface area of the receiving network and helps reroute high volumes of traffic to more data centers.
Traffic scrubbing centers are data centers that are designed to filter out malicious traffic from legitimate traffic. They are used to mitigate DDoS attacks by filtering out the attack traffic and forwarding clean traffic to the customer’s servers. When a DDoS attack occurs, the traffic is routed through the scrubbing center, where it is analyzed and filtered. The clean traffic is then forwarded to the customer’s servers.

Hybrid Cloud-Based DDoS Mitigation

Moving DDoS mitigation efforts to a hybrid solution can bring the best of public cloud security and private cloud or on-premises management. A hybrid model can allow businesses to further tailor their security posture to their unique data needs.

Application DDoS Mitigation

Apps are the drivers of modern business, but they are increasingly targeted for DDoS attacks. Traditional DDoS mitigation is static and centralized. But because apps are distributed across clouds and architecture, they need a DDoS mitigation solution that is scalable and flexible to offer maximum protection.

Components of DDoS Mitigation

A comprehensive DDoS mitigation strategy typically includes several key components.

Traffic Analysis and Monitoring

The first step in DDoS mitigation is detecting potential issues or risks. The two main methods of identifying and alerting on threats are signature-based detection and anomaly-based detection.

Signature-based detection relies on a preprogrammed list of known indicators of compromise (IOCs) to identify threats. These IOCs could include malicious network attack behavior, content of email subject lines, file hashes, known byte sequences, or malicious domains, among other issues. Signature-based detection has high processing speed for known attacks and low false positive rates, but it cannot detect zero-day exploits.

Anomaly-based detection, on the other hand, is capable of alerting on unknown suspicious behavior. Anomaly-based detection involves first training the system with a normalized baseline and then comparing activity against that baseline; once it detects something out of the ordinary, an alert is triggered. Anomaly-based detection can have higher false positive rates.

Real-Time Traffic Diversion

Protecting DNS resources is business critical. Two real-time traffic diversion solutions can help.

DNS redirection involves redirecting DNS queries from one domain name to another. This can be useful in situations where a website has moved to a new domain name or when a company wants to redirect traffic from one domain name to another. DNS redirection can be implemented using a CNAME record in the DNS zone file. When a DNS query is received for the original domain name, the DNS server responds with a CNAME record pointing to the new domain name. The client then sends a new DNS query for the new domain name.
BGP Anycast involves advertising the same IP address from multiple locations on the Internet. In BGP Anycast, the Border Gateway Protocol (BGP) is used to advertise the IP address from multiple locations. When a client sends a DNS query to an Anycast IP address, the query is routed to the nearest location that is advertising the IP address. This can help to improve the performance and availability of DNS services by reducing latency. BGP Anycast is typically used by large organizations that have multiple data centers located in different geographic regions.

Attack Filtering and Cleaning

As traffic moves toward and through your network, you need a DDoS mitigation solution that is continually monitoring it for malicious activity.

Identification of malicious traffic works by examining traffic coming from the client before it is sent on its way to the application tier, ensuring that malicious traffic never passes the proxy barrier. Traffic returning from the server can be fully examined before it is deemed acceptable to pass back to the client. That helps ensure that sensitive data such as credit card numbers or PII are never passed across the proxy barrier.
Scrubbing algorithms and techniques are used to find and delete malicious traffic as it comes into your network. Scrubbing centers are the first stop for traffic; at the centers, traffic is triaged based on traffic characteristics and possible attack methodologies. Traffic continues to be checked as it traverses the scrubbing center to confirm the malicious traffic has been fully removed. This security control is critical because DDoS attacks can easily overwhelm ingress pipes into the customer environment.

DDoS Mitigation Factors to Consider When Choosing a Provider

When considering the right DDoS mitigation solution for your organization’s needs you will want to weigh the following factors with your business’s growth trajectory and possible risk surface in mind. And when and if you are considering a cloud service, you now have the option of choosing among several public clouds (AWS, Google Cloud, Microsoft Azure, and Alibaba Cloud) as well as private cloud companies.

Factors to Consider When Choosing a DDoS Mitigation Provider

Scalability: The solution should be able to handle the traffic volume of the company’s network and scale up or down as needed.
Flexibility: The solution should be flexible enough to adapt to the changing nature of DDoS attacks and be able to protect against new attack vectors.
Reliability: The solution should be reliable and able to detect and mitigate attacks in real-time without affecting legitimate traffic.
Cost-effectiveness: The solution should be cost-effective and provide value for money.
Ease of use: The solution should be easy to deploy, configure, and manage.
Support: The solution should have a responsive support team that can provide assistance when needed

Best Practices for DDoS Mitigation

A comprehensive DDoS mitigation solution helps cover your network preventively, with real-time incident response, and ongoing testing and review to ensure the highest performance.

Proactive Measures

Network architecture design: A well-designed network architecture can help prevent DDoS attacks by ensuring that the network is resilient and can withstand high volumes of traffic. For example, a network that is designed with multiple layers of security, including firewalls, intrusion detection systems, and other security measures, can help prevent DDoS attacks from penetrating the network. Additionally, network segmentation can help limit the impact of an attack by isolating affected areas of the network.

Load balancing: Load balancing can help prevent DDoS attacks by distributing traffic across multiple servers, which can help prevent any one server from becoming overwhelmed. This can help ensure that the network remains available even during a DDoS attack. Load balancers can also help detect and block malicious traffic, which can help prevent DDoS attacks from succeeding.

Detailed vendor SLAs: When considering a third party for DDoS attacks protection, it’s critical to understand the vendor’s capabilities in every DDoS scenario, and to have protocols, actions, and responses incorporated into the SLA.

Incident Response

DDoS incident handling steps: There are six key steps involved in responding quickly and effectively to a DDoS incident, though it’s important to state that these steps don’t happen in a linear fashion, but rather in a loop.

Preparation: Establish contacts, define procedures, and gather tools to save time during an attack.
Detection: Detect the incident, determine its scope, and involve the appropriate parties.
Analysis: Analyze the attack traffic to determine its characteristics and identify the target.
Containment: Contain the attack by filtering traffic and blocking malicious traffic.
Eradication: Eradicate the attack by removing malicious traffic from the network.
Recovery: Recover from the attack by restoring services and reviewing the incident.

Communication protocols with mitigation provider during a DDoS incident: From the outset, it’s key for a company and its mitigation provider to follow a strict communication protocol. These are recommended best practices for communication during an incident:

Establish a communication plan: Establish a communication plan with your DDoS mitigation provider before an attack occurs. This plan should include contact information for key personnel, escalation procedures, and communication channels.
Provide detailed information: Provide your DDoS mitigation provider with detailed information about the attack, including the type of attack, the target, and the duration of the attack. This information can help your provider develop an effective mitigation strategy.
Collaborate with your provider: Work closely with your DDoS mitigation provider to develop a mitigation strategy that is tailored to your organization’s needs. This may include adjusting traffic routing, filtering traffic, or blocking malicious traffic.
Monitor the situation: Monitor the situation closely and provide regular updates to your DDoS mitigation provider. This can help your provider adjust their mitigation strategy as needed.
Review the incident: After the attack has been mitigated, review the incident with your DDoS mitigation provider to identify areas for improvement and update your incident response plan as needed.

Regular Testing and Review

IT and security teams should be doing analysis and testing regularly. One type of testing is red team testing, which involves simulating real-world attackers’ tactics and techniques. In this case, the red team testers would try out a variety of DDoS attacks to monitor the responses of the mitigation solution.

It’s also critical to stay up to date on trends in cyberattacks, especially as bad actors from around the world continue to change their methods. A mitigation solution should be scalable and adaptable to any new types of disruptions.

DDoS Mitigation Case Studies

Organizations in any vertical, of any size, operating in any part of the world, can benefit from having a reliable DDoS mitigation solution in place. These case studies demonstrate how effective a DDoS mitigation solution can be in any scenario. Companies just like yours have seen measurable results from taking on DDoS risks.

Case study: Learn how a leading insurance company thwarted an attempted DDoS attack, while helping protect its applications and users.
Video: Learn how F5 helped an email provider stop a consolidated its network equipment to reduce potential attack surface and enhance operational security.

Future Trends in DDoS Mitigation

While DDoS attacks have been around for decades, the bad actors who operate them are growing ever more sophisticated and aggressive. It’s important to be aware of current and coming trends in the DDoS area of cybersecurity.

At a high level, F5 has found these trends in 2023:

Application layer attacks are up by 165%
The technology sector takes the top spot as most attacked compared with 2022
Overall observed events are down by -9.7%
Peak bandwidth up 216% from 2020
All verticals should expect to see more application and multi-vector DDoS

In addition, there are three growing areas that cybersecurity experts are keeping an eye on:

Artificial intelligence and machine learning: As more companies are deploying AI and ML in other parts of their businesses, like manufacturing or customer service, there are roles they can play in detecting and mitigating DDoS attacks. One recent study showed that using an artificial intelligence method to detect DDoS attacks resulted in more than 96 percent accuracy.

Internet of Things (IoT): IoT is growing, yet securing the additional compute surfaces involved can leave these solutions more vulnerable to attack. Experts suggest adopting more robust security practices, password protection, and using firewalls or VPS, all to reduce the number of devices at risk to attack. 

Blockchain technology: Blockchain technology presents an interesting option for DDoS mitigation because by its nature, blockchain is decentralized and has secured distributed storage. That can help especially with geographic attacks, where security can also be targeted geographically.

While DDoS attacks are not going away, there are more tools to help mitigate those attacks both now and into the coming years.

How F5 Can Help

Distributed Denial of Service (DDoS) attacks have been around for decades, and they are not going away. That’s why companies need to be thinking future-forward for their DDoS mitigation solutions. At F5, cybersecurity is front and center of virtually everything we do. Our DDoS mitigation solutions and stellar support give your organization the upper hand it needs in mitigating the risks of possible DDoS attacks. It’s also important to make sure your DDoS mitigation solution can scale and adapt to your company’s needs – and to the adapting threat of DDoS bad actors.

Let F5 help you in all the ways you and your network might need DDoS attack protection. We have deep experience in implementing the right type of DDoS mitigation for your organization’s needs.