Tackling and Mitigating a Distributed Network attack

A Distributed Denial of Service (DDoS) attack on a public website can have severe consequences for businesses, including lost revenue, reputational damage, and even legal liability. DDoS attacks involve overwhelming a website with traffic from multiple sources, making it inaccessible to legitimate users.

There was a high-volume DDoS attack recently on one of the public sites that I am responsible for. I was in the midst of all the action around the clock and helped mitigate this issue. There was an initial glitch, but the site has been running stable for the customers, with a lot of work done behind the scenes.

We did have a finely tuned WAF layer, but this was a pure layer 7 volumetric attack from across the Globe and was purposely targeting the application layer. The attack was staggered with throughput in millions of requests per minute. Most well-known WAFs available in the market with Advanced DDoS protection and ML-based pattern detections have limitations at such high volumes.  

Some of the  best practices to prevent a DDoS attack includes

Implement DDoS protection measures

The first step in tackling a DDoS attack is to implement DDoS protection measures. These measures can include firewalls (WAF), load balancers, and intrusion prevention systems (IPS). Additionally, businesses can use cloud-based DDoS protection services, which can automatically detect and mitigate attacks. The protection needs to be done at different layers of OSI design. Also, most modern WAF products have managed rules along with advanced Bot protection that needs to be fine-tuned.  

Develop a response plan

Organizations should have a plan in place for how to respond to a DDoS attack. This kind of attack can happen at any time and a proper plan should include a response team, communication protocols, and steps to address the attack. Additionally, another key element is that teams should regularly test their plan to ensure it is effective. 

Monitor network traffic

Monitoring network traffic is critical in identifying a DDoS attack on a public website. This can be achieved by using network traffic analysis tools that can identify spikes in traffic and alert the security team in real time. Capturing logs along with ready-made queries can help identify and monitor malicious traffic. 

Block malicious traffic

One of the most effective ways to mitigate a DDoS attack is to block malicious traffic. This can be achieved by using access control lists (ACLs) and firewalls to block traffic from known malicious IP addresses or Geo Locations. Additionally, teams can use rate limiting, geo-blocks, automatic pattern detection, and URL blocks to limit the amount of traffic coming from specific sources.

Use Content Delivery Networks (CDNs)

CDNs can help to mitigate the impact of a DDoS attack by distributing traffic across multiple servers. This can help to absorb the attack and keep the website online. Additionally, CDNs can offer DDoS protection services that can automatically detect and mitigate attacks.

Tooling and Testing

Having appropriate alerts and notifications along with pattern detection can help identify malicious traffic from time to time. Performing a shadow DDoS test along with timely load testing the infrastructure can help to size the application appropriately. 

Educate users

Finally, teams should educate their users about the risks of DDoS attacks and how to prevent them. This can be achieved through regular training and awareness campaigns. Additionally, businesses can encourage users to report any suspicious activity or traffic they observe.

In conclusion, a DDoS attack on a public website can have significant consequences for businesses. There is no one solution to prevent an attack and the mitigation plan varies from application to application. But the key here is to understand the events of malicious traffic and address specific attack vectors. Also, having a WAF and continuous tuning of the WAF is required to maximize app protection without causing false positives. 

Distributed Denial of service attacks on different OSI layers - Part 3

A Distributed Denial of Service (DDoS) attack is a malicious attempt to make a network or website unavailable to its users by overwhelming it with traffic from multiple sources. These attacks can occur at different layers of the Open Systems Interconnection (OSI) model, and each layer presents different challenges for mitigation. In this article, we will discuss DDoS attacks on different OSI layers with examples.

Layer 3 (Network Layer)

DDoS attacks at the network layer target the routing of IP packets. These attacks aim to consume network bandwidth, making the targeted service unavailable to legitimate users. An example of a network layer DDoS attack is the Ping of Death attack, where an attacker sends oversized ping packets to a target, causing the system to crash or become unavailable.

Mitigation strategies for network layer DDoS attacks include implementing access control lists (ACLs) to filter out unwanted traffic and deploying routers with built-in DDoS protection features.

Layer 4 (Transport Layer)

DDoS attacks at the transport layer target the transport protocol, such as Transmission Control Protocol (TCP) or User Datagram Protocol (UDP). These attacks aim to consume server resources, making the targeted service unavailable to legitimate users. An example of a transport layer DDoS attack is the SYN flood attack, where an attacker sends a flood of TCP SYN requests to a server, consuming server resources and causing the service to become unavailable.

Mitigation strategies for transport layer DDoS attacks include implementing rate limiting and implementing SYN cookies to prevent SYN flood attacks.

Layer 7 (Application Layer)

DDoS attacks at the application layer target the application protocol, such as HTTP or HTTPS. These attacks aim to consume server resources, making the targeted service unavailable to legitimate users. An example of an application layer DDoS attack is the HTTP Flood attack, where an attacker sends a large number of HTTP requests to a server, consuming server resources and causing the service to become unavailable.

Mitigation strategies for application layer DDoS attacks include implementing web application firewalls (WAFs) to filter out unwanted traffic, implementing rate limiting, and using CDN services to distribute the load across multiple servers.

In conclusion, DDoS attacks can occur at different layers of the OSI model, and each layer presents unique challenges for mitigation. Mitigation strategies for DDoS attacks include implementing ACLs, deploying routers with built-in DDoS protection features, implementing rate limiting, using SYN cookies, implementing WAFs, and using CDN services. By being prepared and implementing these strategies, businesses can mitigate the risks of DDoS attacks and ensure their systems remain available to legitimate users.