A Distributed Denial of Service (DDoS) attack is a malicious attempt to disrupt the normal functioning of a network, service, or website by overwhelming it with a flood of illegitimate traffic. In a DDoS attack, multiple compromised computers or devices, often referred to as “botnets,” are coordinated to send a massive volume of requests or data packets to the target, causing it to become overwhelmed and unable to handle legitimate user requests.
The main objective of a DDoS attack is to exhaust the target’s resources, such as bandwidth, processing power, or memory, rendering it inaccessible to legitimate users. This can result in service interruptions, downtime, financial losses, and damage to the reputation of the targeted entity.
DDoS attacks can be categorized into several types based on the techniques used:
Volumetric Attacks: These attacks aim to consume the target’s bandwidth by flooding it with a high volume of traffic. The goal is to saturate the network infrastructure, making the service unavailable. Examples include UDP floods and ICMP floods.
TCP State-Exhaustion Attacks: These attacks exploit the stateful nature of TCP connections. By overwhelming the target’s resources that handle the TCP connections, such as the server’s ability to track connections or allocate memory for them, the attacker can exhaust the server’s capacity to handle legitimate requests. SYN floods and ACK floods are common examples.
Application Layer Attacks: These attacks target specific applications or services running on the target’s server, aiming to exhaust its computing resources or exploit vulnerabilities. Examples include HTTP floods, which flood the target with HTTP requests, and Slowloris attacks, which attempt to exhaust server resources by keeping connections open for as long as possible.
Protocol Attacks: These attacks exploit weaknesses in network protocols or infrastructure components to disrupt the target’s services. Examples include DNS amplification attacks, where the attacker sends a small DNS query with a forged source IP address, causing the DNS server to respond with a larger reply to the victim.
Mitigating DDoS attacks requires a combination of proactive planning and real-time response. Organizations employ various security measures and mitigation techniques, such as:
Traffic Filtering: Employing firewalls, load balancers, or intrusion prevention systems (IPS) to filter out malicious traffic and allow only legitimate traffic to reach the target.
Rate Limiting: Setting up thresholds and rate limits to restrict the number of requests or connections from a single source, mitigating the impact of an attack.
Anomaly Detection: Implementing monitoring systems that can identify abnormal traffic patterns or behavior and automatically trigger mitigation actions.
Content Delivery Networks (CDNs): Utilizing CDNs, like Cloudflare, that distribute website content across multiple servers, helping absorb and mitigate the impact of DDoS attacks by spreading the traffic.
DDoS Mitigation Services: Employing specialized DDoS mitigation services that employ advanced detection and mitigation techniques, often with large-scale network capacity, to absorb and filter out attack traffic before it reaches the target.
DDoS attacks continue to evolve, with attackers employing new techniques and amplification methods. As a result, organizations must remain vigilant, regularly update their security measures, and have effective response plans in place to minimize the impact of DDoS attacks.