What is the difference between DDoS and DOS attack?

It is important to first understand a DoS (Denial of Service) attack before discussing the difference between DoS and DDoS (Distributed Denial of Service) attacks. A Denial of Service (DoS) attack occurs when an attacker attempts to overwhelm a target service, such as a website, server, application, or network, by sending thousands of simultaneous requests from a single device. This flood of requests can render the targeted service or application unavailable to legitimate users.

This attack directly impacts an organization's availability by making its services inaccessible to legitimate users.

There are multiple ways to make service unavailable for legitimate users by manipulating network packets, programming, or resource handling vulnerabilities but Denial of service (Dos) is most popular and easy to launch attack against target.

For Example: If a social media site can handle 100 requests per second, then to make this service unavailable the attacker only need to send more than 100 fake requests per second to make the service unavailable for the legitimate users.

Dos attacks typically fall in two categories:

1. The most common type of Denial of Service (DoS) attack is a buffer overflow attack, which occurs when more traffic is directed to a network address than the system can handle. This can manifest in various ways, including:

   • ICMP Flood: An Internet Control Message Protocol (ICMP) DoS attack, also known as a ping flood attack, is a common type of DoS attack where an attacker tries to overwhelm the target device with ICMP echo requests (pings). Typically, ICMP echo requests and echo replies are used to ping a network device to check its health and connectivity between the sender and receiver.

     In a ping flood attack, by flooding the target with ICMP echo requests, the network is forced to respond with an equal number of reply packets. This results in the target becoming inaccessible to normal traffic (legitimate users).

   • SYN Flood Attack: In a SYN flood attack, the attacker takes advantage of the handshake process by sending thousands of SYN requests to the server without completing the handshake. This leaves the server with numerous half-open connections, consuming its resources and preventing it from responding to legitimate users.

     As a result, the server's capacity is overwhelmed, making it unable to process valid requests from real users. Such attacks are particularly damaging to systems offering Transmission Control Protocol (TCP) services, such as web servers, email servers, and file transfer systems.

2. Flood attacks: In a flood attack, the attacker inundates the server with an excessive number of data packets. As the server processes these fake requests, it becomes overwhelmed and exhausts its resources, such as bandwidth and processing power. This leaves the server unable to manage legitimate user requests, resulting in a denial-of-service (DoS).

   For this type of attack to be effective, the attacker typically needs more bandwidth (or network capacity) than the targeted server. By sending an overwhelming number of packets, the attacker can overload the server, causing it to stop responding correctly.

What is the difference between a DDoS attack and a DOS attack?

DoS (Denial-of-Service):In a DoS attack, the attacker floods the target with numerous requests from a single device, overwhelming the system. Since the requests originate from one source, it is easier to detect and block the attack.

DDoS (Distributed Denial-of-Service):In a DDoS attack, the attacker uses a network of compromised devices, known as a botnet, to send a massive volume of fake requests to the target. Because these requests come from multiple sources, distinguishing between legitimate users and the attack becomes much more difficult.

How to identify a DOS attack is executed against your Network

There are multiple signs of DoS attacks which can be identified by users. Common signs are: -

·       Slow network performance for common tasks such as loging into an account, accessing a website or streaming audio or video content, downloading/uploading files.

·       Unable to access online resources like bank accounts, educational materials, health records, websites, or web-based accounts, and investment portfolios.

·       An interruption or loss of connectivity for multiple devices on the same network.

Prevention and Mitigation of Denial-of-Service Attacks: 

• Firewalls and Filtering Mechanisms: Use firewalls that will prevent malicious traffic from reaching the target destination. Install rules that prohibit access from questionable IP addresses.

• Rate Limitation: Cap the number of requests a server receives from one device to avoid overwhelming the system.

• Load Balancing: Direct incoming traffic to several servers so that the load on a particular server is decreased.

• Anti-DDoS Services: Utilize Anti DDoS Services such as:

  • Traffic Filtering: Anti-DDoS services use traffic filtering techniques to distinguish between legitimate and malicious traffic. This involves inspecting incoming data packets and blocking or redirecting suspicious traffic.

  • Rate Limiting: Rate limiting helps by restricting the number of requests a server can process from a specific source within a set period. This prevents an attacker from overwhelming the system with too many requests.

  • Real-Time Monitoring: Anti-DDoS services constantly monitor network traffic for unusual spikes, which are indicative of an ongoing DDoS attack. This real-time analysis enables swift identification of attack patterns and rapid countermeasures.

  • Traffic Anomaly Detection: Anti-DDoS solutions analyze network traffic and use machine learning algorithms to recognize unusual patterns that could indicate a DDoS attack, such as sudden spikes in traffic or irregular access patterns.

  •  Geofencing: Some Anti-DDoS services can block or limit traffic from specific geographical regions if the attack is originating from those areas. This allows businesses to protect themselves from targeted attacks from particular locations.

  • Anycast Network: Anycast routing directs incoming traffic to the nearest available data center, which helps distribute the traffic load and mitigate the impact of DDoS attacks. This ensures that traffic is processed by the closest server, making it more resilient against attacks.

  • Content Delivery Networks (CDNs): CDNs cache content on multiple servers across the globe, reducing the load on the origin server. This can help absorb the impact of DDoS attacks by distributing the malicious traffic across many servers.

  • Web Application Firewalls (WAF): WAFs protect web applications by filtering and monitoring HTTP traffic. When used alongside Anti-DDoS services, they can block malicious traffic targeting specific vulnerabilities in applications.

  • Bot Detection and Mitigation: Anti-DDoS services often include bot detection mechanisms that identify and block automated traffic from bots or botnets used in DDoS attacks.

  • Scrubbing Centers: When an attack occurs, the incoming traffic is redirected to a scrubbing center, where malicious traffic is removed, and clean traffic is forwarded to the target system. This ensures that the target remains operational during an attack.

• Network Monitoring: Monitor the network activities to determine any abnormal increases in traffic and respond quickly.

• Strong Network Architecture: Design the network infrastructure to withstand sudden surges in traffic by implementing redundancy and failover mechanisms.