What is Distributed Denial of Service (DDoS)?

Distributed Denial of Service (DDoS) attacks happen when malicious actors attempt to disrupt the regular functioning of targeted servers, services, websites, or networks by overwhelming them with a deluge of Internet traffic. Unlike a Denial of Service (DoS) attack, which typically uses a single source, a DDoS attack leverages multiple compromised computer systems as sources of attack traffic.

These multiple systems, often located across various geographical areas, generate high volumes of traffic, making it difficult to mitigate the attack by blocking traffic from a single IP address. The primary goal of a DDoS attack is to make its target unavailable to its users.

How DDoS attacks work

DDoS attacks exploit the fundamental communication protocols of the internet to flood a target with an overwhelming amount of traffic. Here’s a general overview of how they work:

Botnet Creation: Attackers first build a network of infected computers, known as a botnet. These machines are compromised through malwareWhat is Malware? Malware, a portmanteau of “malicious software,” constitutes a broad category of software specifically designed to infiltrate, damage, or disrupt computer systems, networks, and devices without the user’s… and can be controlled remotely without the owners’ knowledge.

Traffic Generation: The attacker instructs the botnet to generate vast amounts of traffic directed at the target. This traffic can take various forms, such as multiple protocol requests.

Traffic Surge: The influx of traffic overwhelms the target’s resources, including bandwidth, processing power, and memory. Legitimate traffic must contend with getting through, leading to service degradation or complete shutdown.

Persistence: The attack can be sustained over a prolonged period, increasing the difficulty of mitigation and recovery efforts.

The different types of DDoS

DDoS attacks can be classified into several types based on their methodology and the target of the attack:

Volume-Based Attacks: These aim to consume the bandwidth of the target site or network. Examples include UDP floods, ICMP floods, and other spoofed-packet floods. The primary goal is to saturate the bandwidth of the targeted site, making it difficult for legitimate traffic to pass through.

Protocol Attacks: These types of attacks exploit weaknesses in the protocols underpinning internet communication. Examples include SYN floods, fragmented packet attacks, ping, and other packet-based attacks. Protocol attacks consume server resources or intermediate communication equipment like load balancers and firewalls.

Application Layer Attacks: These attacks are the most sophisticated, complex, and challenging to defend against because they target specific web applications. Examples include HTTP floods and DNSWhat is DNS? The Domain Name System (DNS) is a critical component of the internet, functioning like a phone book for the digital world. It translates user-friendly domain names, such… attacks. These attacks mimic legitimate user traffic, making them harder to detect and block.

How organizations can protect themselves from DDoS

Entities can employ several strategies to protect against DDoS attacks:

DDoS Mitigation Services: Specialized services like Cloudflare, Akamai, and Arbor Networks provide protection by absorbing and filtering malicious traffic before it can achieve its goals. These services have extensive infrastructures capable of handling large volumes of traffic.

Rate Limiting: Implementing rate-limiting on servers and applications can help control the number of requests a server will accept within a specific timeframe, thereby mitigating the impact of a DDoS attack.

Traffic Analysis and Filtering: Deploying Intrusion Detection and Prevention Systems (IDPS) that analyze traffic patterns and filter out suspicious activities can help with early detection and response to DDoS attacks.

Redundancy and Failover: Building redundancy into the network infrastructure, such as using multiple data centers and failover strategies, can help maintain availability even during an attack.

Regular Security Audits: Regular security audits and stress testing can help pinpoint vulnerabilities and ensure that defensive measures are robust and current.

Incident Response Plan: Developing a comprehensive incident response plan that includes steps for identifying, mitigating, and recovering from DDoS attacks can minimize downtime and business impact.

Understanding DDoS attacks and implementing appropriate defensive strategies can significantly reduce the risk of becoming victims of these disruptive attacks.

For more essential cybersecurity definitions, check out our glossary pages here.