A HTTP flood attack is a type of Denial-of-Service (DoS) attack that aims to overwhelm a web server or web application by sending a large number of HTTP requests, thereby disrupting normal operations or rendering the service inaccessible. This is achieved by the attacker sending a large volume of HTTP requests to the target, depleting server resources such as CPU, memory, or network bandwidth.
There are various types of HTTP flood attacks, including:
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HTTP GET Flood: In this attack, the attacker sends a large number of HTTP GET requests to the web server. Each request requests a specific resource or URL from the server, potentially overwhelming the server as it attempts to process all requests simultaneously.
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HTTP POST Flood: Here, the attacker sends a large number of HTTP POST requests to the web server. Unlike GET requests, where the content is included in the URL, the POST request carries data in the HTTP body, potentially requiring the server to consume more resources to process.
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Slowloris Attack: In this attack, the attacker sends a series of HTTP requests to the web server but keeps the connections open by sending the HTTP headers slowly over an extended period. This consumes the limited connections on the web server, preventing legitimate users from accessing the service.
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HTTP Amplification: Here, the attacker manipulates HTTP requests or responses to send a large amount of data to the victim and overwhelm server resources.
HTTP flood attacks can have significant impacts on the availability of web services by slowing down or completely halting the service. To protect against such attacks, organizations often deploy firewalls, intrusion detection systems (IDS), content delivery networks (CDNs), and specialized anti-DDoS services to monitor traffic, detect suspicious activity, and maintain normal operations.
