All about DDoS Attacks and How to Prevent Them

It is vital to have uninterrupted service whether you operate a small business or a personal website. If your website is slow or entirely unavailable, you may lose users and clients.

To build the most satisfactory security solution, every business owner must understand Distributed Denial of Service (DDoS) attacks thoroughly. Navigating DDoS attack types and their key characteristics is an important technique to gain expertise. 

What are DDoS Attacks?

DDoS attacks are carried out via networks of Internet-connected computers. These networks are made up of computers and other devices (such as IoT devices) that have been infected with malware. This allows an attacker to manage them remotely. Individual devices are known as bots (or zombies), while a network of bots is known as a botnet. After establishing a botnet, the attacker may conduct an attack by sending remote commands to each bot.

These attacks try to take down or slow down the targeted website by flooding the network, server, or application with fake traffic. DDoS attacks are malicious attempts to render internet services unavailable to users, frequently causing their hosting server to be temporarily interrupted or suspended. Because each bot is a legitimate Internet device, distinguishing attack traffic from regular traffic can be difficult.

DDoS attacks on websites and organizations of all sizes are common. GitHub was hit by one of the most remarkable DDoS attacks in 2018, taking the company’s website down for ten minutes. A DDoS attack disrupted the BBC’s whole network of websites in 2015. Moreover, numerous South African banking websites were targeted by ransom-driven DDoS attacks in 2019.

How to identify a DDoS attack?

The most visible indication of a DDoS attack is a site or service that becomes unexpectedly slow or inaccessible to legitimate traffic. However, even a minor shift in lawful traffic might cause many problems. Thus it is vital to look at a plethora of additional evidence. Users who have the same behavioral profile, device type, geography, or web browser version will generate a flood of traffic. DDoS attacks’ telltale signals can be detected using traffic analytics software. The server returns a 503 error and a service outage. Ping requests and TTL time-outs are also possible.

What are some common types of DDoS attacks?

Broadly speaking, DoS and DDoS attacks can be divided into three types:

• Application Layer Attacks
• Volume-based Attacks
• Protocol Attacks

Application layer attacks

The purpose of application layer or layer 7 DDoS attacks (referring to the OSI model’s 7th layer) is to deplete the target’s resources and cause a denial of service. Layer 7 attacks are difficult to protect against since it might be difficult to distinguish between malicious and genuine communication.

An application-layer attack targets an application and particular vulnerabilities or flaws, preventing the program from communicating with or delivering content to its users (s).

Application Layer Attacks include low-and-slow attacks, GET/POST floods, and attacks against Apache, Windows, or OpenBSD vulnerabilities, among other things. The scope of the attack is measured in Requests per second (Rps).

The fundamental efficacy of most DDoS attacks stems from the difference between the resources required to launch an attack and the resources required to absorb or neutralize one. While this is true for L7 attacks, the efficiency of influencing both the targeted server and the network needs less total bandwidth to produce the same disruptive effect; an application layer attack does more significant harm with less total bandwidth.

An attacker may use a layer seven or application layer attack to target the application itself. Like SYN flood infrastructure attacks, the attacker attempts to overload particular components of an application to render it inaccessible or unresponsive to legitimate users. This is sometimes possible with very low request volumes that create only a modest amount of network traffic. As a result, the attack may be challenging to identify and neutralize. Examples of application-layer attacks are HTTP floods, cache-busting attacks, and WordPress XML-RPC floods.

An attacker launches a WordPress XML-RPC flood attack, also known as a WordPress pingback flood, against a website running on the WordPress content management platform. The attacker uses the XML-RPC API function to send a flood of HTTP requests. The pingback function allows a WordPress-hosted website (Site A) to alert another WordPress site (Site B) via a link that Site A has built to Site B. Site B then seeks to retrieve Site A to confirm the existence of the link. The attacker leverages this capability in a pingback flood to induce Site B to attack Site A. These attacks have a distinct signature: WordPress is generally included in the HTTP request header’s User-Agent field.

An attacker can choose to exploit the TLS negotiation process if a web application is served through Transport Layer Security (TLS). TLS is computationally costly; therefore, an attacker can degrade service availability by producing extra stress on the server to treat unreadable data (or incomprehensible (ciphertext)) as a genuine handshake. An attacker completes the TLS handshake but constantly renegotiates the encryption mechanism in a variant of this attack. In addition, an attacker can exhaust server resources by opening and closing many TLS sessions.

How can a CDN counteract DDoS attacks?

If your website is the subject of a DDoS attack, a CDN will ensure that the assault does not reach the origin server, rendering your site inoperable. When a server receives more traffic than it can manage, it simply forwards it to other servers. There will be no downtime for your website. Users won’t notice anything, and you won’t either.

Other methods for preventing HTTP floods include the usage of a web application firewall, traffic management and filtering using an IP reputation database, and on-the-fly network monitoring by engineers.

Green Plus CDN can evaluate traffic from several sources, mitigating possible attacks with continually updated WAF rules and other mitigation measures, often before they occur or have a chance to occur.

3 Techniques Mitigate Application Layer DDoS Attacks

Captcha and JavaScript Challenges

CAPTCHA verification is a web technique for determining if a user is a genuine person or a spam machine. CAPTCHAs provide users with altered letters or symbols that must be deciphered by humans. Another method for filtering requests from botnets or attack machines uses JavaScript computational challenges. Most botnets are incapable of dealing with such complicated difficulties.

Behavioral Analytics

Behavioral analytics is a security method that leverages AI and machine learning technologies to analyze and record user and object behavior. It then identifies any unusual activity or traffic that does not fit the typical/daily trends. This approach employs sophisticated analysis, data from logs and reports, and threat data to successfully identify anomalies that may signal hostile behavior. According to computer experts, this strategy allows for the precise detection of rogue actors that may threaten your system.

Web Application Firewall

A web application firewall protects your apps from the internet. An intelligent WAF can manage, filter, and analyze traffic from many sources. WAFs work with the aid of rules and policies that can be easily and quickly customized and updated. This allows it to respond to assaults more quickly. A WAF is the most effective defense against some of the most popular DDoS assaults, including layer seven attacks. Managed WAFs filter layer seven traffic and provide data to cybersecurity specialists who can identify malicious traffic attempting to disrupt your services.