DDoS, or Distributed Denial of Service, is a type of cyberattack where multiple compromised systems are used to flood a target,
Such as a server or web application—with excessive traffic. The goal is to overwhelm the target’s resources, causing disruption to the service. Typically, these attacks are motivated by financial demands, with the attacker threatening to continue the disruption unless a ransom is paid. DDoS attacks can range in duration from a few hours to several days. The longest recorded DDoS attack lasted for 509 hours—more than 21 days—highlighting the scale and persistence of such attacks.
Common Types of DDoS Attacks
Zero-Day DDoS Attacks
These are attacks that exploit previously unknown vulnerabilities, making them especially dangerous as there may be no available defense until a patch is released.
UDP Flood
In a DDoS attack, the User Datagram Protocol (UDP) is commonly exploited by attackers to flood a victim’s host with a large number of UDP packets sent to random ports. This causes the host to become overwhelmed as it performs several checks, including:
- Verifying if an application is listening on the requested port.
- Determining if no application is listening on the port.
- Responding with a packet indicating the host is unreachable.
As the victim’s system receives and processes these numerous requests, it becomes busy attempting to handle each one, ultimately making it unable to respond to legitimate users or other clients.
ICMP Flood
The Internet Control Message Protocol (ICMP), commonly known as “ping,” is used in attacks where multiple ping requests are sent to a server. This can overwhelm the server, causing it to crash. Common commands in such attacks include ping -n, ping -t, and ping -i.
SYN Flood
In a regular connection setup, a client sends a synchronization (SYN) packet, followed by a SYN-ACK response from the server, and then an ACK from the client. However, in a SYN flood attack, the attacker sends SYN packets without responding to the SYN-ACK, causing the server to wait for a response that never arrives, eventually exhausting its resources.
Ping of Death
This attack involves sending an oversized ping packet that exceeds the maximum allowed size of an IP packet (65,535 bytes). This causes the target system to crash or freeze as it tries to process the malformed packet.
Slowloris
A Slowloris attack targets web servers by sending partial HTTP requests and keeping the connections open for as long as possible. This consumes server resources, eventually making the server unresponsive to legitimate users.
NTP Amplification
Network Time Protocol (NTP) servers are typically used to synchronize clocks over the internet. In a DDoS attack, attackers send NTP requests with a spoofed IP address (victim’s address), amplifying the attack by sending large volumes of traffic to the target.
HTTP Flood
An HTTP flood attack involves sending numerous HTTP requests, often using GET and POST methods, to overwhelm the web server. These can target both static content (images, etc.) and dynamic resources (databases, etc.).
Zero-Day DDoS Attacks
These are attacks that exploit previously unknown vulnerabilities, making them especially dangerous as there may be no available defense until a patch is released.
How to Defend Against a DDoS Attack
There are several steps you can take to safeguard your network and systems from a DDoS attack.
Monitor Network Traffic
Using tools like Google Analytics or other traffic monitoring services, you can keep an eye on unusual spikes in traffic that may indicate an ongoing attack.
Run Test DDoS Simulations
To ensure your infrastructure can withstand a DDoS attack, you can simulate DDoS conditions. Several free and open-source tools are available for this, including:
- Low Orbit Ion Cannon
- UDP Unicorn
Install a Firewall
A good firewall can help block malicious traffic before it reaches your network. Consider using both hardware and software firewalls to maximize protection.
Check Activity Logs
Use the netstat command to verify if there are any irregularities in your network activity. Additionally, network analyzers can help identify traffic anomalies.
Deploy Malware Security Scanners
Security scanners can help detect malicious code entering your system and provide alerts when suspicious activity is detected.
WaseerHost Security Mechanism
At WaseerHost, security is our top priority. We’ve implemented advanced, unbreakable security measures on our servers, partnering with BitNinja to provide cutting-edge protection. BitNinja acts as the first line of defense, protecting our clients from DDoS attacks and a wide range of other cyber threats. Their self-learning algorithms continuously improve, ensuring our security system remains up to date.
