How to Prevent L7 DDoS Attacks

3d illustration of skull of death on smartphone screen. ddos attack message on mobile phone on tablet computer

L7 DDoS attacks are a type of denial-of-service attack that can be difficult to prevent. This post will outline the steps to take to prevent these attacks, including implementing redundancies and monitoring the network for anomalies.

Application Layer attacks are a type of attack that uses HTTP requests to bombard a targeted server. These types of attacks are difficult to prevent because the hacker typically uses botnets to flood the website with requests.

The best way to prevent a L7 DDoS attack is to make sure that the website is resistant to them in the first place. These types of attacks are only to occur when the web server is under heavy load and can be prevented by deploying some basic security measures.

Overview of L7 Application layer

The L7 Application layer is responsible for hosting the actual application code. This is an important layer in the stack because it manages the end-user experience.

The Application layer is also responsible for responding to the requests from the Transport layer, and passing the data from the Transport layer to the Session layer.

The Application layer is also responsible for managing the connection between the client and server. This can be done by establishing a TCP connection, or HTTP connection, with the server through the Session layer.

Why L7 DDoS Attacks Are Such a Big Problem?

L7 DDoS attacks are becoming a bigger problem for organizations because they are much more difficult to defend against. Unlike L3 DDoS attacks, which are designed to overwhelm the target’s bandwidth and cause network outages, L7 DDoS attacks.

This type of attack doesn’t rely on network bandwidth to cause damage, but instead targets your applications and how they interact with the target’s infrastructure. L7 DDoS attacks are harder to defend against because they happen at the application layer.

Layer 7 ddos attack type

Layer 7 DDoS attacks are one of the more dangerous types of DDoS attacks. The attack is sent in the form of a request that is more difficult to detect and doesn’t resemble other attack types.

The attack is sent in the form of a request and is more difficult to detect. The purpose of this type of attack is to crash or overload the system by creating too many connections and not being able to handle them.

The attacker sends a large number of requests to the victim server causing it to crash and overload. The large request is sent in the form of a UDP packet which is difficult to detect.

Basic HTTP Floods:

With a name that suggests the simplicity and frequency of their use, these HTTP Flooding attacks are undoubtedly the most common type of attacks. The attackers use the same range of IP addresses, user agents and referrers (smaller in number than volumetric attacks) to gain access to the same webpage or resource over and over again. The server is unable to handle the sudden flow of requests and crashes.

Randomized HTTP Floods:

In this kind of HTTP Flooding attacks, attackers leverage a wide range of IP addresses, randomized URLs/ user agents/ referrers to carry out more complex attacks.

Here, the data packets coming from these botnets may contain more than just the request message. To the server, the request may seem just like any other request with no indication that the content has been maliciously altered.

Cache-bypass HTTP Floods

According to security specialist, attackers are exploiting every possible bandwidth to make the web server expend more resources by executing tasks that cannot be found in cache.

These tasks such as illegal searches and the like, increases the traffic of each individual request, making the website or service more likely to crash and overwhelm the server.

WordPress XML-RPC Floods

A brutal yet creative web attack, the Pingback Flooding Attack is an excellent example of an HTTP Flooding Attack. It involves the malicious perpetrators sending a large number of Pingback requests to a web server.

The server will then respond with a large amount of data, causing the bandwidth to be consumed by a large amount of unnecessary traffic.

Slowloris Attacks

This is the simplest and most lethal type of DDOS attack, and can be delivered by anyone with an internet connection. The Slowloris Attack is a brute force DDOS attack against a website or server using the general purpose operating system TCP port 80.

The Slowloris Attack exploits a weakness in the TCP protocol by sending a large amount of small packets (hence the name “Slowloris”) to overwhelm the targeted web server.

How We Stopped the L7 DDoS Attack?

To prevent from L7 DDoS attacks, traffic should be filtered by type of packet. TCP traffic should be filtered with SYN-ACK packets and UDP and ICMP packets should be filtered with source and destination ports.

An example of a network device that filters packets on the basis of port. The list of ports that are filtered by this device is as follows: A network device, which is used for web filtering, can also filter TCP packets.

This device can filter TCP packets based on the destination port. This is because, the destination port number is used to identify a connection.

A network device that filters UDP and ICMP packets can also filter UDP packets based on the source and destination port.

Conclusion

These types of attacks usually use HTTP Flooding Attacks in order to execute them. Pingback Flooding Attacks are an Application Layer L7 ddos attack that can slow down or crash the web server by sending excessive requests to it.

They can be prevented by making sure the web server has the proper protection mechanisms in place. A Pingback Flooding Attack can be prevented by using a URL Filter.

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