HTTP/HEADERS-Flood Attack
An HTTP/HEADERS-Flood Attack is a type of Denial-of-Service (DoS) attack where the attacker sends numerous HTTP requests with excessive headers to a target server. This is designed to overwhelm the server's resources, leading to denial of service for legitimate users.
Mechanism
The attack involves:
- Generating a high volume of HTTP requests with an unusually large number of headers or headers with extremely long values.
- Exploiting the fact that web servers typically process each header individually, which can consume significant server resources, particularly CPU and memory.
Impact
- Server Overload: The server might become unresponsive or crash due to resource exhaustion.
- Degradation of Service: Even if the server does not crash, the response time for legitimate requests can degrade significantly.
- Resource Consumption: The attack can lead to increased consumption of bandwidth, memory, and processing power, affecting other services running on the same infrastructure.
Historical Context
HTTP/HEADERS-Flood attacks have been documented since the early 2000s when web services became more prevalent. They were part of the broader evolution of DoS and DDoS attacks as attackers sought new methods to bypass traditional mitigation techniques:
- In 2002, the Blaster Worm included elements of HTTP flooding in its attack vectors.
- By 2010, attackers started using HTTP/HEADERS-Flood more frequently due to the increasing complexity and size of web applications.
- Recent years have seen an increase in the sophistication of these attacks, with attackers using botnets to distribute the load across multiple sources.
Defense and Mitigation
- Rate Limiting: Implementing rate limits on the number of headers or requests per client to prevent abuse.
- Header Validation: Checking and rejecting headers that exceed predefined thresholds for size or number.
- Web Application Firewalls (WAFs): Using WAFs to detect and block malicious traffic patterns associated with header flooding.
- Load Balancers: Employing load balancers to distribute traffic and handle requests more efficiently.
Sources
Related Topics