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Distributed Denial of Service (DDoS) Attacks

Protecting Your Organizations Against DDoS Attacks

October 10, 2023


In the digital age, where companies and individuals are heavily dependent on the Internet, the threat of cyber-attacks is enormous. Among these threats, DDoS (Distributed Denial of Service) attacks stand out as a particularly powerful and destructive form of cyberattack. The aim of this article is to shed light on the complexities of DDoS attacks including a review of the various types of DDoS and how to prevent and defend against them.

What is a DDoS Attack?

A Distributed Denial of Service (DDoS) attack is a malicious attempt to disrupt the normal functioning of a targeted website, service, or network by overloading it with traffic. Unlike traditional Denial of Service (DoS) attacks, where a single source dominates the target, DDoS attacks are coordinated actions involving multiple attacked devices and are often distributed across multiple locations. These devices, known as "botnets," are typically infected computers, smartphones, or other internet-connected devices that have been hijacked by cybercriminals without their owners' knowledge.

Causes of DDoS Attacks 

Distributed Denial of Service (DDoS) attacks are orchestrated by malicious actors with the goal of disrupting the normal functioning of the targeted website, service, or network. These attacks are characterized by generating massive amount of traffic, which makes the targeted resource inaccessible to legitimate users. DDoS attacks can be motivated by a variety of factors, and understanding their root causes is critical to successfully preventing and mitigating these threats. Here are some common causes of DDoS attacks:

  • Financial Gain: Some DDoS attacks are carried out to extort money. The attackers demand a ransom from the targeted organization and threaten to continue the attack or increase its intensity if their demands are not met. This type of attack is commonly referred to as "Ransom DDoS" or "Ransom DDoS".
  • Competitive Advantage: In highly competitive industries, competing companies may use DDoS attacks against competitors to gain a competitive advantage. By disrupting a competitor's online services, the company can redirect potential customers to its own platforms.
  • Hacktivism: Hacktivists are individuals or groups with strong ideological or political beliefs who use DDoS attacks to further their goals or to raise awareness of specific issues. These attacks often involve making a statement or drawing attention to something.
  • Revenge: Some DDoS attacks are carried out out of revenge or retaliation. Individuals or groups may target an organization or individual they believe has harmed them in some way.
  • Political Motives: Nation-states or politically motivated groups can use DDoS attacks to disrupt an adversary's online presence, for example on government websites, to express opposition, demonstrate capabilities, or undermine an adversary's credibility.
  • Distraction for Other Attacks: DDoS attacks can be used as a diversionary tactic to distract from other cybercrimes such as data breaches or malware infiltration. By overloading an organization's security team with a DDoS attack, attackers can exploit vulnerabilities in other parts of the system.
  • Testing and Experimentation: Some attackers may conduct DDoS attacks to test their skills, tools, or techniques. These attacks may have no clear reason other than to demonstrate skills or explore the possible effects of different attack methods.
  • Ideological Beliefs: Like hacktivism, some individuals or groups may conduct DDoS attacks to further their ideological beliefs, even if those beliefs are not clearly related to a political issue. This can include attacks on organizations that contradict or differ from their beliefs.
  • Personal Satisfaction: Some people launch DDoS attacks purely out of personal satisfaction or a sense of power and control. Disrupting the services of a large organization can give an attacker thrill or boost their ego.
  • Unintentional Participation: In some cases, malware-infected devices can unknowingly become part of a botnet and participate in a DDoS attack. This can be due to lax security practices, outdated software, or lack of awareness on the part of the device owner.

Types of DDoS Attacks

There are several types of DDoS attacks, each with its own approach and impact:

  1. Volumetric Attacks: Volumetric attacks are a type of Distributed Denial of Service (DDoS) attack that focuses on flooding the target system, network, or website with overwhelming traffic. The purpose of these attacks is to saturate the target's available resources to prevent it from responding to legitimate user requests, thus triggering a denial of service.

    In a volumetric attack, the attacker harnesses the power of a botnet, a network of compromised devices (such as computers, servers, IoT devices, and even smartphones) that have been infected with malware and are under the attacker's control. These devices are commonly called "bots". By coordinating the actions of these compromised devices, the attacker generates a large amount of targeted traffic. There are two main categories of traffic used in volumetric attacks:
    • Legitimate Traffic: In some cases, attackers can exploit legitimate user traffic for a volumetric attack. By directing a barrage of genuine user requests at the target, the attacker attempts to exhaust the target's resources such as bandwidth, processing power, and memory. This approach is effective because the target system has difficulty distinguishing between legitimate and malicious traffic, making it difficult for attackers to filter the traffic.
    • Junk Data (Garbage Traffic): Alternatively, attackers can generate large amounts of unwanted or meaningless data and send it to the target. This unwanted traffic does not necessarily consist of valid requests but is intended to consume the target's resources by overloading its incoming processing capacity.

      The effects of volumetric attacks can be severe and destructive. The target system's infrastructure becomes overloaded, resulting in legitimate users experiencing slow or unresponsive services. Excessive traffic can lead to network congestion, slower loading and, in extreme cases, a complete shutdown of the service.

      Defending against volumetric attacks requires a combination of proactive measures and reactive responses:

    • Traffic Filtering: Advanced traffic and network filtering helps detect and block malicious traffic patterns related to volumetric attacks. This can include the use of firewalls, intrusion detection and prevention systems (IDPS) and advanced threat intelligence.
    • Content Delivery Networks (CDNs): CDNs are used to distribute network traffic across multiple servers and data centers. By balancing the load, CDNs can absorb a significant portion of the attacker's traffic, reducing the impact on the target system.
    • Anomaly Detection:  Anomaly detection tools can be used to identify abnormal traffic patterns in real time. When a traffic spike is detected, automated responses can be triggered to redirect, filter, or block malicious traffic.
    • Traffic Scrubbing Services: Third-party DDoS protection services specialize in identifying and mitigating volumetric attacks. These services filter malicious traffic, allowing legitimate traffic to reach its destination, minimizing the impact of the attack.
    • Scalable Infrastructure: Building a scalable network infrastructure that can handle higher traffic volumes is critical. Cloud-based services and load balancers help distribute traffic and prevent bottlenecks.
  2. Protocol Attacks: Protocol attacks are a type of distributed denial-of-service (DDoS) attack that exploits vulnerabilities in the communication protocols that underlie the workings of the Internet and computer networks. These attacks aim to overload the targeted system by targeting specific vulnerabilities in these protocols, consuming system resources and making it inaccessible to legitimate users.

    Two common examples of protocol attacks are SYN flood attacks and Ping of Death attacks:
    • SYN Flood Attack: In a SYN flood attack, the attacker exploits the workings of the Transmission Control Protocol (TCP) when a connection is first established between the client and the server. 
    • The TCP handshake involves a three-step process: SYN (sync), SYN-ACK (acknowledgment of synchronization), and ACK (acknowledgment). In a SYN flood attack, the attacker sends a large number of SYN requests to the target server, but never completes the final phase of the handshake by sending an ACK response.
    • This causes the target server to maintain a backlog of half-open connections, consuming valuable resources and ultimately leading to a denial of service. Legal users cannot connect to the server because they are running out of resources.
    • Ping of Death Attack: The Ping of Death attack exploits vulnerabilities in the Internet Control Message Protocol (ICMP), which is used for network diagnostics and error reporting. In a Ping of Death attack, the attacker sends oversized or fragmented ICMP packets to the target system. These packets are larger than the system can handle, and buffer overflows or crashes may occur when the system attempts to reassemble or process them. This will make the target system unstable or unresponsive, denying access to authorized users.

      Mitigating protocol attacks requires a combination of understanding the attack methods and implementing preventive measures:
    • Traffic Analysis and Filtering: Use network traffic analysis tools and intrusion detection systems to detect and filter anomalous traffic patterns related to protocol attacks. These systems can identify and block malicious packets before they reach the target system.
    • Rate Limiting: Implements rate limiting mechanisms that limit the number of connection requests or packets that the system can receive in each period. This can help avoid an overwhelming flow of requests during an attack.
    • TCP Handshake Improvements: Implement changes to the TCP handshake process to detect and mitigate SYN flood attacks. For example, SYN cookies can be used to track half-open connections without maintaining large status tables.
    • Firewalls and Security Appliances: Use firewalls and security devices designed to detect and block malicious or malformed traffic at the edge of your network.
    • Patch and Update Systems: Regularly update and patch network devices, servers, and software to fix known vulnerabilities that can be exploited in protocol attacks.
    • Intrusion Prevention Systems (IPS): Implements IPS solutions that can identify and block malicious traffic patterns in real-time to prevent protocol attacks from reaching the targeted system.
  3. Application Layer Attacks: Application layer attacks, also known as Layer 7 attacks, are a sophisticated form of Distributed Denial of Service (DDoS) attacks that target the top layer of the Open Systems Interconnection (OSI) model: the application layer. Unlike other types of DDoS attacks that focus on overwhelming network resources, application layer attacks exploit vulnerabilities in software, web applications, or services running on the targeted server. These attacks are particularly difficult to contain because they often mimic legitimate user behavior, making it difficult to distinguish between normal and malicious traffic.

Here's an explanation of application layer attacks and their characteristics:

  • Targeting the Application Layer: Application-level attacks directly target the applications and services that users interact with. This includes web servers, content management systems, online shopping carts, APIs and other application-specific functions. Attackers exploit vulnerabilities in these apps to disrupt their normal functioning and prevent legitimate users from accessing the services.
  • Mimicking Legitimate User Behavior: One of the characteristics of application layer attacks is the ability to mimic legitimate user behavior. Attackers craft requests that closely resemble legitimate user interactions, e.g. B. sending HTTP requests, submitting forms or performing searches. This makes it difficult for traditional security mechanisms to differentiate between malicious traffic and normal traffic.

Variety of Attack Techniques: Application layer attacks include a variety of techniques, including but not limited to:

  • HTTP Flood: Sending a large volume of seemingly legitimate HTTP requests to overwhelm the target's web server or application.
  • Slowloris: Keeping many connections to the target's server open, consuming resources and causing slow performance.
  • SQL Injection: Exploiting vulnerabilities in input fields to inject malicious SQL code that disrupts database operations.
  • Cross-Site Scripting (XSS): Injecting malicious scripts into web pages that are then executed by users' browsers, potentially leading to data theft or disruption.
  • Layer 7 DDoS Botnets: Using a network of compromised devices to flood the application layer with requests, often targeting specific URLs or API endpoints.

Challenges in Mitigation: Application layer attacks are difficult to mitigate for several reasons:

  • Traffic Legitimacy: Attack traffic closely resembles legitimate user interactions, making it hard to filter out malicious requests without affecting legitimate users.
  • Resource-Intensive: Application layer attacks can consume significant server resources, such as CPU and memory, even with relatively low traffic volumes.
  • Advanced Techniques: Attackers continuously evolve their tactics, making it challenging for security solutions to keep up with emerging attack methods.

Mitigating Application Layer Attacks:

  • Web Application Firewalls (WAFs): WAFs are specialized security solutions that analyze incoming traffic and filter out malicious requests before they reach the application. They use rulesets and behavioral analysis to identify and block suspicious activity.
  • Rate Limiting: Implement rate limiting on API endpoints and other application functions to restrict the number of requests from a single source within a specified timeframe.
  • Behavioral Analysis: Employ anomaly detection and behavioral analysis tools to identify patterns of traffic that deviate from normal user behavior.
  • Content Delivery Networks (CDNs): CDNs can help distribute traffic and filter out malicious requests before they reach the origin server.
  • Regular Security Audits: Conduct regular security audits and vulnerability assessments on your applications to identify and patch potential weaknesses.

Impacts of DDoS Attacks

The consequences of a successful DDoS attack can be severe and wide-ranging:

  • Service Disruption: DDoS attacks are specifically designed to overwhelm target resources such as bandwidth, processing power, and memory. As a result, the target website, application, or online service becomes unavailable or significantly slower. Authorized users cannot access the services they use, which frustrates them, and may force them to look for alternatives. This disruption can last beyond the immediate duration of the attack, as corrective action can take some time.
  • Financial Loss: Prolonged downtime because of a successful DDoS attack can result in significant financial losses for organizations. For example, online retailers can miss sales opportunities during peak periods. In addition, service level agreements (SLAs) with customers or partners can be breached, which can lead to financial penalties. Enterprises may also need to invest in additional infrastructure or DDoS mitigation services to prevent future attacks that incur additional costs.
  • Reputation Damage: Unavailability of online services due to DDoS attack can undermine customer trust. Users experiencing outages may find the organization unreliable or unable to provide stable services. This loss of trust can lead to customer churn, negative online reviews, and damage to a company's brand reputation. After an attack it can be difficult for companies to regain customer loyalty and restore their image.
  • Data Breach Risk: DDoS attacks can serve as a distraction or cover for more insidious cybercrimes such as data breaches or malware infiltrations. As security teams focus on mitigating DDoS attacks, attackers can exploit organizational vulnerabilities to gain unauthorized access to sensitive data. This can lead to the theft of valuable information, including customer personal information, financial records, and intellectual property.
  • Operational Disruption: DDoS attacks not only directly affect digital services but can also disrupt internal operations and business processes. Employees may not have access to critical resources, resulting in reduced productivity. Communication between team members and external partners can also be compromised, impacting collaboration and decision-making.
  • Legal and Regulatory Consequences: Depending on the industry and the type of services provided, organizations may face legal and regulatory ramifications after a DDoS attack. Failure to protect customer data or maintain the availability of services can result in lawsuits, fines, and government investigations.
  • Customer Support Overload: During and after a DDoS attack, customer service teams can be inundated with requests from frustrated users asking for help. This increased demand can strain resources and further impair a company's ability to respond effectively.

Prevention and Mitigation

Prevention and mitigation are critical strategies to effectively defend against Distributed Denial of Service (DDoS) attacks, which can disrupt online services and cause significant harm to organizations. By implementing a multi-faceted approach that combines various cybersecurity measures, organizations can enhance their resilience against DDoS attacks. Here's an explanation of the recommended prevention and mitigation strategies:

  1. Network Infrastructure: Deploying a robust network infrastructure is essential for handling and mitigating DDoS attacks. This includes:
  2. Firewalls: Implementing firewalls to filter and block malicious traffic at the network perimeter.
  3. Intrusion Detection and Prevention Systems (IDPS): IDPS solutions can identify and block suspicious traffic patterns in real-time, helping to prevent DDoS attacks from reaching the target system.
  4. Load Balancers: Load balancers distribute incoming traffic across multiple servers, preventing any single server from becoming overwhelmed during an attack.
  5. Content Delivery Networks (CDNs): CDNs are a crucial line of defense against DDoS attacks, especially volumetric attacks. They distribute traffic across a network of servers geographically dispersed, absorbing and mitigating traffic spikes before they reach the target's origin server. CDNs help to maintain service availability and minimize the impact of DDoS attacks on the target system.
  6. Anomaly Detection: Implementing advanced monitoring systems that can detect unusual traffic patterns and behavior is vital. These systems use machine learning and behavioral analysis to identify deviations from normal traffic. When abnormal patterns are detected, automated responses can be triggered to divert, filter, or block malicious traffic.
  7. Web Application Firewalls (WAFs): WAFs are designed to protect against application layer attacks by filtering and blocking malicious traffic at the application layer itself. They use rule-based and behavioral analysis techniques to distinguish between legitimate user requests and malicious traffic. By preventing attacks from reaching the application, WAFs help maintain the integrity and availability of online services.
  8. Traffic Scrubbing Services: Third-party DDoS mitigation services specialize in identifying and filtering out malicious traffic. These services operate upstream from the target's network and use sophisticated traffic analysis techniques to distinguish between legitimate and malicious traffic. Legitimate traffic is allowed to pass through while malicious traffic is "scrubbed" or removed.

The Crucial Importance of DDoS Protection

Distributed Denial of Service (DDoS) attacks pose a serious and evolving threat to organizations, businesses, and individuals in the digital landscape. Implementing robust DDoS protection is essential for several compelling reasons:

  • Maintaining Service Availability: DDoS attacks are designed to overwhelm target resources, causing service disruptions or even complete outages. By having DDoS protection in place, organizations can ensure that their online services remain accessible to legitimate users, maintaining business continuity and preventing revenue loss.
  • Protecting Reputation and Customer Trust: DDoS attacks that lead to service downtime or disruptions can damage an organization's reputation. Customers and partners rely on consistent and reliable access to online services. Failing to provide this can erode trust, lead to customer dissatisfaction, and result in long-term reputation damage.
  • Preventing Financial Loss: Downtime caused by DDoS attacks can result in immediate and significant financial losses. Businesses may lose out on sales opportunities, experience decreased productivity, and face penalties from SLA violations. DDoS protection helps mitigate these financial impacts by minimizing service disruptions.    
  • Mitigating Operational Disruptions: Beyond financial losses, DDoS attacks can disrupt internal operations, affecting employee productivity, communication, and collaboration. Effective protection helps ensure that internal operations can continue smoothly despite external attack attempts.
  • Reducing Attack Surface: DDoS protection solutions can help identify and filter out malicious traffic, reducing the attack surface and the potential for other cybercrimes. Attackers may use DDoS attacks as a smokescreen to divert attention from more insidious activities, such as data breaches or malware infiltration.
  • Compliance and Regulatory Requirements: Many industries have specific regulatory and compliance requirements related to cybersecurity and data protection. Implementing DDoS protection measures can help organizations meet these requirements and avoid potential legal and financial consequences.
  • Enhancing Incident Response: Having DDoS protection in place improves an organization's incident response capabilities. With the right solutions and strategies, an organization can detect and mitigate DDoS attacks quickly, minimizing the duration and impact of an attack.
  • Maintaining Competitive Advantage: A successful DDoS attack that disrupts an organization's services can provide a competitive advantage to rivals. Competitors may gain customers and market share if they are able to maintain service availability while the targeted organization is struggling.
  • Preventing Brand Damage: Organizations spend significant resources building and maintaining their brand image. DDoS attacks can lead to negative publicity, tarnishing the brand's reputation and leading to long-term damage that affects customer perception.


Tags:  Managed Services