An HTTPS flood is a type of distributed denial-of-service (DDoS) attack that targets web servers and applications by overwhelming them with a high volume of HTTPS requests. These requests can be either GET or POST, and they are designed to exhaust the server's processing capacity and bandwidth, leading to a slowdown or complete crash of the targeted service. This type of attack exploits the HTTPS protocol, which is commonly used for secure communication over the internet.

Unlike other DDoS attacks that may use malformed packets or spoofing techniques, an HTTPS flood relies on legitimate-looking requests, making it harder to detect and mitigate. The attack typically involves a botnet—a network of compromised computers—that generates the flood of requests. By leveraging the secure nature of HTTPS, attackers can make it even more challenging for traditional security measures to differentiate between malicious and legitimate traffic.

How does an HTTPS Flood Work?

HTTPS flood attacks operate by leveraging the secure nature of HTTPS requests to overwhelm a server's resources. Attackers typically use botnets, which are networks of compromised devices, to generate a massive volume of HTTPS GET or POST requests. These requests appear legitimate, making it difficult for traditional security measures to distinguish between normal and malicious traffic.

The encrypted nature of HTTPS adds another layer of complexity. Each request must be decrypted by the server before it can be processed, consuming additional computational resources. This decryption process, combined with the sheer volume of requests, can quickly exhaust the server's capacity, leading to a slowdown or complete crash.

Moreover, HTTPS flood attacks exploit the server's need to allocate resources for each incoming request. POST requests, in particular, can be more resource-intensive as they often trigger complex server-side operations. By inundating the server with these processing-heavy requests, attackers can effectively disrupt service availability.

What are Examples of HTTPS Floods?

Examples of HTTPS flood attacks can be seen in various real-world scenarios. One notable instance involved Imperva mitigating a massive attack that generated 690,000,000 DDoS requests from 180,000 botnet IPs. This attack demonstrated the sheer scale and complexity that HTTPS floods can reach, overwhelming even robust security measures.

Another example includes the use of HTTP GET and POST requests to retrieve static content or trigger complex server-side operations. These methods are often employed to maximize the resource strain on the targeted server, making it difficult for traditional security measures to distinguish between legitimate and malicious traffic. Such attacks highlight the importance of advanced mitigation strategies to ensure service availability.

What are the Potential Risks of An HTTPS Flood?

• Service Disruption: An HTTPS flood can cause significant downtime, making websites or applications unavailable to legitimate users.

• Financial Losses: Downtime from an attack can lead to lost revenue and increased operational costs due to the need for additional resources to handle the attack.

• Reputation Damage: Frequent or prolonged service outages can harm a company's reputation, leading to a loss of customer trust and potential long-term business impact.

• Resource Exhaustion: The attack can deplete server resources, forcing the organization to invest in additional bandwidth and server capacity.

• Legal Consequences: Failure to protect against such attacks could result in legal issues, especially if service level agreements (SLAs) are violated.

How can you Protect Against An HTTPS Flood?

Protecting against an HTTPS flood requires a multi-faceted approach. Here are some effective strategies:

• Traffic Profiling: Continuously monitor and analyze traffic patterns to identify and block abnormal activity.

• Web Application Firewall (WAF): Deploy WAFs to filter and monitor HTTP traffic, blocking malicious requests before they reach the server.

• Progressive Security Challenges: Implement challenges like CAPTCHA or JavaScript parsing to differentiate between legitimate users and bots.

• IP Reputation Tracking: Use IP reputation databases to block traffic from known malicious sources.

• Cloud-based DDoS Protection: Leverage cloud-based services for real-time threat detection and mitigation, ensuring quick response to suspicious activity.