Distributed Denial-of-Service (DDoS) attacks are indeed a prevalent type of cyberattack. In a DDoS attack, the attacker overloads a network, service, or server with traffic to the point that it is no longer available to users. This is usually done by controlling multiple systems and using them to target a single system, hence the term “distributed.”
Here’s how bad actors typically execute DDoS attacks:
Botnets: The attackers infect numerous computers (sometimes in the millions) with malware to turn them into “bots” or “zombies.” These systems are remotely controlled by the attacker and can be used to generate massive amounts of traffic.
Amplification Attacks: In this type of DDoS attack, an attacker sends a small amount of data to a server or service, causing it to send a large amount of data to a victim’s IP address. A common form of this is a DNS amplification attack, where an attacker sends a DNS query with a spoofed IP address to a DNS server. The DNS server then sends a large amount of data to the victim’s IP address.
Reflection Attacks: These are similar to amplification attacks. The attacker spoofs the victim’s IP address and sends a request to a server. The server then sends a response to the victim’s IP address, flooding it with traffic.
Application Layer Attacks: These target a specific application on a server, rather than the server itself. For example, an attacker might target a web application on a server by sending it a large number of requests, causing it to become overloaded and stop working.
TCP Connection Attacks: These overwhelm the target system’s ability to maintain a TCP connection table (a data structure that tracks all connections to a system). This can be done through SYN floods or other similar methods, where the attacker sends a large number of requests to establish a TCP connection but never completes the process, causing the connection table to fill up and denying service to legitimate users.
Preventing DDoS attacks involves a mix of measures including:
Increasing Bandwidth: One of the simplest ways to prevent a DDoS attack is by having more bandwidth available than the attacker can fill. However, this can be expensive and isn’t a complete solution as very large attacks can still exceed available bandwidth.
DDoS Protection Services: Several companies offer DDoS protection services that help absorb the extra traffic generated by a DDoS attack, often through a combination of multiple globally distributed servers and advanced traffic filtering.
Intrusion Detection Systems (IDS): These systems monitor network traffic for suspicious activity and issue alerts when such activity is detected.
Firewalls and Routers: Configuring these devices properly can help block certain types of DDoS attacks. For instance, they can be set up to drop incoming ICMP packets or block DNS responses from outside your network.
Rate Limiting: This can slow down the traffic to manageable levels.
Remember, no solution can guarantee complete protection from DDoS attacks, but a combination of the above can significantly reduce the risk and potential impact of an attack.