What is a Slowloris DDoS Attack?

Slowloris DDoS attack is one of many DDoS attacks. DDoS attacks are a potential threat to online businesses. One must know how to stay protected from such attacks. This post is dedicated to the Slowloris DDoS attack. We will know what is a Slowloris DDoS attack, how it works, and how to fight back. Such attacks are very stealthy & persistent in nature. So, let’s begin!

What is a Slowloris DDoS Attack?

A Slowloris DDoS attack is designed to exhaust server resources by keeping many connections to the target web server open and holding them open as long as possible. This attack method allows a single machine to impact another server’s services by overloading it with open connections rather than bandwidth or processing power.

Unlike traditional DDoS attacks that flood servers with lots of unwanted traffic, Slowloris operates by initiating many concurrent connections to the target server and deliberately keeping them open & active.

How Does Slowloris DDoS Attack Work?

Initiating Connections

The target servers start receiving partial HTTP requests from the attackers. Such requests establish multiple connections without completing the requests. This exhausts server resources and stops them from serving genuine users.

Keeping Connections Alive

Slowloris DDoS attack keeps each connection open by sending incomplete HTTP headers frequently and continuously. These headers are designed to keep the connection open indefinitely, tying up server resources.

Resource Exhaustion

Over time, as the number of open connections increases, the target server’s capacity to accept new connections diminishes. Eventually, genuine users stop establishing connections to the server after some time, leading to the loss of business.

Characteristics of Slowloris DDOS Attacks

Slowloris DDOS attacks are characterized by several key features. These features differentiate them from other Distributed Denial of Service (DDoS) attacks.

Low Bandwidth Requirement

Unlike traditional DDoS attacks that require high traffic volumes – Slowloris can effectively bring down a server with relatively low bandwidth usage.

Stealth & Longevity

Slowloris is designed to operate quietly & persistently. It can evade detection by generating traffic patterns that mimic genuine user behavior, making it harder to distinguish from regular traffic.

Resource Efficiency

Slowloris consumes server resources such as TCP connections & memory rather than network bandwidth. It focuses on keeping connections open rather than generating new ones.

Impacts of Slowloris DDOS Attacks

The consequences of a successful Slowloris DDOS attack can be severe for the targeted server & its users.

Service Disruption

The primary impact is denial of service to legitimate users, as the server becomes overwhelmed and unable to respond to their requests.

Financial Losses

Businesses relying on the targeted server can suffer financial losses due to disrupted services, lost sales, and damage to their reputation.

Operational Costs

Mitigating & recovering from Slowloris attacks require significant time, effort, and financial resources.

How to Mitigate Slowloris DDOS Attacks?

Given the stealthy nature of Slowloris attacks, effective mitigation requires a combination of proactive measures and rapid response capabilities. You can do the following to mitigate Slowloris DDOS attacks.

Increase Server Limits

Adjust server settings to allow more concurrent connections, reducing the impact of Slowloris attacks.

Rate Limiting

Utilize rate limiting on incoming connections to detect and block malicious connections attempting to exploit server resources.

Web Application Firewall (WAF)

Deploy a WAF to detect and block suspicious HTTP traffic, including Slowloris attack patterns.

Monitoring & Anomaly Detection

Monitor server logs and network traffic continuously for unusual patterns or prolonged connections that may indicate a Slowloris attack in progress.

Update & Patch

Keep server software, web servers, and operating systems updated with the latest security patches to mitigate vulnerabilities exploited by Slowloris attacks.

Traffic Analysis

Use traffic analysis tools to differentiate between legitimate user traffic and malicious Slowloris traffic – enabling faster detection.

Real-World Examples of Slowloris DDOS Attacks

Several high-profile incidents have demonstrated the effectiveness & impact of Slowloris attacks.

• In 2009, websites, including Twitter, Flickr, and more – experienced disruptions due to Slowloris attacks. It shows the vulnerability of even large-scale services to such attacks.

• More recently, Slowloris attacks have been used against government websites, financial institutions, and e-commerce platforms like Amazon – underscoring the ongoing threat posed by this attack vector.

Conclusion

Slowloris DDoS attacks are an evolving threat to online services and web servers. Exploiting servers to handle HTTP connections, Slowloris can render a server inaccessible to authentic users without the need for vast bandwidth or computational resources. To defend against Slowloris attacks, you must adopt the multi-layered approach mentioned above. You can safeguard your online presence and minimize the risk of disruption caused by these stealthy cyber threats by being aware & active.

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