How does a Slowloris attack work?

Slowloris is an application layer attack which operates by utilizing partial HTTP requests. The attack functions by opening connections to a targeted Web server and then keeping those connections open as long as it can.

Slowloris is not a category of attack but is instead a specific attack tool designed to allow a single machine to take down a server without using a lot of bandwidth. Unlike bandwidth-consuming reflection-based DDoS attacks such as NTP amplification, this type of attack uses a low amount of bandwidth, and instead aims to use up server resources with requests that seem slower than normal but otherwise mimic regular traffic.https://ps4booter.netfalls in the category of attacks known as low and slow attacks. The targeted server will only have so many threads available to handle concurrent connections. Each server thread will attempt to stay alive while waiting for the slow request to complete, which never occurs. When the servers maximum possible connections has been exceeded, each additional connection will not be answered and denial-of-service will occur.

A Slowloris attack occurs in 4 steps:
The attacker first opens multiple connections to the targeted server by sending multiple partial HTTP request headers.
The target opens a thread for each incoming request, with the intent of closing the thread once the connection is completed. In order to be efficient, if a connection takes too long, the server will timeout the exceedingly long connection, freeing the thread up for the next request.
To prevent the target from timing out the connections, the attacker periodically sends partial request headers to the target in order to keep the request alive. In essence saying, Im still here! Im just slow, please wait for me.
The targeted server is never able to release any of the open partial connections while waiting for the termination of the request. Once all available threads are in use, the server will be unable to respond to additional requests made from regular traffic, resulting in denial-of-service.
The key behind a Slowloris is its ability to cause a lot of trouble with very little bandwidth consumption.