What Is HTTP/2 Rapid Reset Attack And The Mitigation

Imagine that you’re driving on a highway, and suddenly, your car’s engine stalls, leaving you stranded. Now, think of this scenario in the digital realm, where websites, instead of cars, face sudden breakdowns due to vulnerabilities. This is precisely what the HTTP/2 Rapid Reset Vulnerability feels like in the world of the internet – a sudden and unexpected glitch that can bring down even the most robust websites. In this article, we will understand what is HTTP/2 Rapid Reset Attack and explore the crucial steps for mitigation.


Understanding HTTP/2: The Backbone of Modern Internet

Before diving into the depths of the HTTP/2 Rapid Reset Vulnerability, it’s essential to comprehend what HTTP/2 is. HTTP/2, the second major version of the HTTP network protocol, is the backbone of the modern internet. It was developed to enhance the performance of websites, making them faster and more efficient. HTTP/2 speeds up the website page loading by allowing multiple simultaneous requests to a website over a single TCP (Transport connection Protocol) connection. However, every innovation comes with its set of challenges, and HTTP/2 is no exception.


What is HTTP/2 Rapid Reset Attack?



What Is HTTP/2 Rapid Reset Attack

Picture credits: Google.


On 10th October 2023, Google disclosed a zero-day vulnerability in the HTTP/2 protocol.

HTTP/2 Rapid Reset is a term that has been echoing in the digital corridors lately. But what does it mean?

Picture your website as a fortress in the digital realm. Imagine a scenario where an attacker finds a hidden passage, breaching the fortress walls. This is precisely what the HTTP/2 Rapid Reset Attack does. It exploits the vulnerability in the HTTP/2 protocol, creating a passage for cybercriminals to infiltrate websites and wreak havoc.

HTTP/2 Rapid Reset Attack is a layer 7 DDOS attack. DDOS means distributed denial of service.

This attack was significantly larger than any Layer 7 attacks previously, with the largest attack of 398 million requests/second.

In simple words, it refers to a vulnerability within the HTTP/2 protocol that allows malicious actors to exploit certain conditions, causing a rapid reset of connections and DDoS (Distributed Denial of service) attacks. This sudden reset disrupts the communication between servers and clients, leading to potential downtime for websites.


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Understanding CVE 2023-44487


What does this alphanumeric jumble signify? Well, CVE stands for Common Vulnerabilities and Exposures, and it uniquely identifies a specific vulnerability.

One of the buzzwords associated with this vulnerability is CVE 2023-44487. In this case, CVE 2023-44487 is the identification number for the HTTP/2 Rapid Reset Vulnerability, serving as a digital fingerprint for this issue.


How Does HTTP/2 Rapid Reset Attack Work?


To understand the attack simply, imagine a crowded library. HTTP/2 Rapid Reset Attack is akin to a disruptive person, knocking down bookshelves. The chaos caused by these disruptions leads to confusion, making it difficult for the librarian (server) to assist the visitors ( end users). In the digital world, this translates to interrupted connections and unresponsive websites.

HTTP/2 Rapid Reset Attack is a DDos attack at layer 7 ( The application layer of OSI model). In this attack, the attacker automates the process of sending millions of requests at the same time on a website that uses HTTP/2. For a request, the client normally waits for a response and then sends another request but in a Rapid Reset attack, the client sends the request and cancels that request immediately after that and puts a lot of load on the site web server and causing a huge performance impact on and results into the server breakdown.

There are mainly two types of variations while sending the request to the server:

The first variant does not immediately cancel the request but creates a group of requests at once, then waits and then cancels the request. After this, it immediately opens up another connection and makes a group.

In the second variant, the attacker cancels the request completely and opens up more concurrent requests.



Mitigating HTTP/2 Rapid Reset: Protecting the Digital Landscape


We should apply mitigations per vendor instructions and website owners and developers must take proactive measures for HTTP/2 Rapid Reset Mitigation.

We have a top Cyber security leader Imperva who collaborated proactively with Google and got more insights into this vulnerability. As per the company, Imperva’s existing DDoS mitigation policies/signatures effectively defend against this vulnerability. Imperva’s R&D team is further monitoring this vulnerability and will also release updates and patches if required.

Imperva’s quick response to threats like HTTP/2 Rapid Reset shows that it is a cyber security leader in the world.

Think of it as fortifying the castle walls to fend off potential intruders. Here are some effective strategies to protect your digital assets:


1. Regular Updates and Patch Management

Just like your smartphone needs updates, so do the servers. Regularly updating the server software ensures that known vulnerabilities are patched, making it difficult for attackers to exploit weaknesses.


2. Implementing Web Application Firewalls (WAFs)

Web Application Firewalls act as vigilant sentinels, monitoring incoming traffic and filtering out malicious requests. By implementing a robust WAF, websites can defend against various cyber-attacks, including HTTP/2 Rapid Reset Attacks. We have many WAFs available in the market but Imperva WAF is known for its brand value.


3. Load Balancing and Failover Systems

Imagine a skilled juggler keeping multiple balls in the air. Load balancing distributes web traffic across multiple servers, ensuring no single server is overwhelmed. Additionally, failover systems act as safety nets, seamlessly switching to backup servers if the primary server falters due to an attack.


4. Encryption and SSL/TLS Certificates

Encryption is akin to a secret code language that only the sender and receiver understand. SSL/TLS certificates encrypt data transmitted between users and servers, ensuring secure communication. Implementing robust encryption protocols strengthens the website’s defences against malicious attacks.


5. Continuous Monitoring and Incident Response

Vigilance is the key to cybersecurity. Implement continuous monitoring systems that detect unusual activities promptly. In the event of an incident, having a well-defined incident response plan can minimize damage and facilitate a swift recovery.



In the vast landscape of the internet, vulnerabilities like the HTTP/2 Rapid Reset remind us of the importance of digital security. By understanding the nature of these threats and implementing proactive measures, we can navigate the digital terrain safely, ensuring seamless online experiences for everyone. We can take proactive measures to safeguard our websites and servers.


FAQs: What You Need to Know


FAQ 1: What exactly is HTTP/2 Rapid Reset Vulnerability? HTTP/2 Rapid Reset Vulnerability is a flaw in the HTTP/2 protocol, allowing attackers to disrupt connections rapidly. This can lead to website downtime and interrupted user experiences.

FAQ 2: Can HTTPS protect against HTTP/2 Rapid Reset Attacks? While HTTPS provides encryption, it alone cannot fully protect against HTTP/2 Rapid Reset Attacks. Implementing a combination of encryption, regular updates, and web application firewalls is crucial for comprehensive security.

FAQ 3: How often should server software be updated to prevent this vulnerability? Server software should be updated promptly whenever security patches are released. Regular updates are essential to ensure that known vulnerabilities, including HTTP/2 Rapid Reset, are patched.

FAQ 4: Are all websites equally vulnerable to HTTP/2 Rapid Reset Attack?

No, not all websites are equally vulnerable. The susceptibility depends on various factors, including the server’s configuration, security measures in place, and how promptly updates are applied. Websites with robust security protocols are less likely to fall victim to HTTP/2 Rapid Reset Attacks.

FAQ 5: What should I do if my website falls victim to a Rapid Reset Attack? If your website experiences a Rapid Reset Attack, it’s essential to act swiftly. First, isolate the affected server to prevent the attack from spreading. Then, contact your web hosting provider and inform them of the situation. Work closely with cybersecurity experts to analyze the attack, identify vulnerabilities, and fortify your defences to prevent future incidents.

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