What is DDoS?

A Distributed Denial-of-Service (DDoS) attack is a type of cyber-attack designed to make a machine, network resource, or website unavailable to its intended users by overwhelming it with a flood of malicious traffic.

Key Characteristics

• Distributed Nature: Unlike a Denial-of-Service (DoS) attack which originates from a single source, a DDoS attack comes from multiple compromised systems (often referred to as a botnet) spread across different networks and geographic locations234.

• Overwhelming Traffic: The attackers flood the target with an enormous amount of traffic, such as HTTP requests, UDP packets, or other types of network traffic. This overwhelms the target's resources, including bandwidth, CPU, and memory, making it difficult or impossible for legitimate users to access the service124.

• Types of Attacks: DDoS attacks can target various layers of the network, including the network layer (e.g., UDP flooding), transport layer (e.g., SYN flooding), and application layer (e.g., HTTP flooding). They can also involve techniques like DNS amplification, where attackers use spoofed IP addresses to generate large responses from DNS servers that are then directed at the victim34.

• Impact: The effects of a DDoS attack can range from degraded performance and slow response times to complete unavailability of the targeted service. This can result in significant disruptions to businesses, including financial losses, damage to reputation, and compromise of sensitive information125.

Methods and Tools

• Botnets: DDoS attacks often rely on botnets, which are networks of compromised devices (including computers, IoT devices, and other networked resources) controlled remotely by the attackers. These bots can be instructed to send traffic to the target simultaneously, amplifying the attack's impact234.

• Advanced Techniques: Modern DDoS attacks can be highly sophisticated, involving advanced reconnaissance, tactical execution, and the use of multiple attack vectors. For example, advanced persistent DDoS (APDoS) attacks can persist for weeks, involving continuous and coordinated efforts to evade defensive measures3.

Mitigation

• Defense in Depth: Effective mitigation of DDoS attacks involves a combination of on-premises and cloud-based solutions. This includes rapid detection and response mechanisms, as well as the ability to block a wide range of DDoS attack types24.

• Differentiating Traffic: One of the key challenges in mitigating DDoS attacks is differentiating between legitimate and malicious traffic. Advanced solutions often use sophisticated algorithms and real-time monitoring to identify and filter out attack traffic24.

In summary, DDoS attacks are powerful and evolving cyber threats that can significantly impact the availability and performance of online services, making robust defense strategies essential for protecting against them.