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In today’s always-online world, we take uninterrupted access to websites, apps, and digital services for granted. But lurking in the background is a cyber threat that can grind everything to a halt in an instant: DDoS attacks. These attacks don’t sneak in to steal data or plant malware—they’re all about chaos and disruption, flooding servers with so much traffic that they crash, slow down, or completely shut off.

Over the years, DDoS attacks have evolved from annoying nuisances to full-blown cyber weapons, capable of hitting massive scales—some even reaching terabit-level traffic. Companies have lost millions of dollars due to downtime, and even governments and critical infrastructure have been targeted. Whether you’re a CTO, a business owner, a security pro, or just someone who loves tech, understanding these attacks is key to stopping them before they cause real damage.

That’s where this blog series comes in. We’ll be breaking down everything you need to know about DDoS attacks—how they work, real-world examples, the latest prevention strategies, and even how you can leverage Azure services to detect and defend against them.

This will be a three-part series, covering:

🔹Unmasking DDoS Attacks (Part 1): Understanding the Fundamentals and the Attacker’s Playbook

What exactly is a DDoS attack, and how does an attacker plan and execute one? In this post, we’ll cover the fundamentals of DDoS attacks, explore the attacker’s perspective, and break down how an attack is crafted and launched. We’ll also discuss the different categories of DDoS attacks and how attackers choose which strategy to use.

🔹 Unmasking DDoS Attacks (Part 2): Analyzing Known Attack Patterns & Lessons from History

DDoS attacks come in many forms, but what are the most common and dangerous attack patterns? In this deep dive, we’ll explore real-world DDoS attack patterns, categorize them based on their impact, and analyze some of the largest and most disruptive DDoS attacks in history. By learning from past attacks, we can better understand how DDoS threats evolve and what security teams can do to prepare.

🔹 Unmasking DDoS Attacks (Part 3): Detection, Mitigation, and the Future of DDoS Defense

How do you detect a DDoS attack before it causes damage, and what are the best strategies to mitigate one? In this final post, we’ll explore detection techniques, proactive defense strategies, and real-time mitigation approaches. We’ll also discuss future trends in DDoS attacks and evolving defense mechanisms, ensuring that businesses stay ahead of the ever-changing threat landscape.

So, without further ado, let’s jump right into Part 1 and start unraveling the world of DDoS attacks.

What is a DDoS Attack?

A Denial-of-Service (DoS) attack is like an internet traffic jam, but on purpose. It’s when attackers flood a website or online service with so much junk traffic that it slows down, crashes, or becomes completely unreachable for real users.

Back in the early days of the internet, pulling off a DoS attack was relatively simple. Servers were smaller, and a single computer (or maybe a handful) could send enough malicious requests to take down a website. But as technology advanced and cloud computing took over, that approach stopped being effective. Today’s online services run on massive, distributed cloud networks, making them way more resilient.

So, what did attackers do? They leveled up. Instead of relying on just one machine, they started using hundreds, thousands, or even millions—all spread out across the internet. These attacks became “distributed”, with waves of traffic coming from multiple sources at once. And that’s how DDoS (Distributed Denial-of-Service) attacks were born.

Instead of a single attacker, imagine a botnet—an army of compromised devices (anything from hacked computers to unsecured IoT gadgets)—all working together to flood a target with traffic. The result? Even the most powerful servers can struggle to stay online.

In short, a DDoS attack is just a bigger, badder version of a DoS attack, built for the modern internet. And with cloud computing making things harder to take down, attackers have only gotten more creative in their methods.

An Evolving Threat Landscape

As recently reported by Microsoft: “DDoS attacks are happening more frequently and on a larger scale than ever before. In fact, the world has seen almost a 300 percent increase in these types of attacks year over year, and it’s only expected to get worse [link]“. Orchestrating large-scale DDoS botnets attacks are inexpensive for attackers and are often powered by leveraging compromised devices (i.e., security cameras, home routers, cable modems, IoT devices, etc.).

Within the last 6 months alone, our competitors have reported the following:

• June 2023: Waves of L7 attacks on various Microsoft properties


• March 2023: Akamai – 900 Gbps DDoS Attack


• Feb 2023: Cloudflare mitigates record-breaking 71 million request-per-second DDoS attack


• August 2022: How Google Cloud blocked the largest Layer 7 DDoS attack at 46 million rps

Graphs below are F5 labs report. 

Figure 1 Recent trends indicate that Technology sector is one of the most targeted segments along with Finance and Government

Figure 2 Attacks are evolving & a large % of attacks are upgrading to Application DDoS or a multi-vector attack

As the DDoS attacks gets bigger and more sophisticated, we need to take a defense-in-depth approach, to protect our customers in every step of the way. Azure services like Azure Front Door, Azure WAF and One DDoS are all working on various strategies to counter these emerging DDoS attack patterns. We will cover more on how to effectively use these services to protect your services hosted on Azure in part-3. 

Understanding DDoS Attacks: The Attacker’s Perspective

There can be many motivations behind a DDoS attack, ranging from simple mischief to financial gain, political activism, or even cyber warfare. But launching a successful DDoS attack isn’t just about flooding a website with traffic—it requires careful planning, multiple test runs, and a deep understanding of how the target’s infrastructure operates.

So, what does it actually mean to bring down a service? It means pushing one or more critical resources past their breaking point—until the system grinds to a halt, becomes unresponsive, or outright collapses under the pressure. Whether it’s choking the network, exhausting compute power, or overloading application processes, the goal is simple: make the service so overwhelmed that legitimate users can’t access it at all.

Resources Targeted During an Attack

Network Capacity (Bandwidth and Infrastructure): The most common resource targeted in a DDoS attack, the goal is to consume all available network capacity, thereby preventing legitimate requests from getting through. This includes overwhelming routers, switches, and firewalls with excessive traffic, causing them to fail.

Processing Power: By inundating a server with more requests than it can process, an attacker can cause it to slow down or even crash, denying service to legitimate users.

Memory: Attackers might attempt to exhaust the server’s memory capacity, causing degradation in service or outright failure.

Disk Space and I/O Operations: An attacker could aim to consume the server’s storage capacity or overwhelm its disk I/O operations, resulting in slowed system performance or denial of service.

Connection-based Resources: In this type of attack, the resources that manage connections, such as sockets, ports, file descriptors, and connection tables in networking devices, are targeted. Overwhelming these resources can cause a disruption of service for legitimate users.

Application Functionality: Specific functions of a web application can be targeted to cause a denial of service. For instance, if a web application has a particularly resource-intensive operation, an attacker may repeatedly request this operation to exhaust the server’s resources.

DNS Servers: A DNS server can be targeted to disrupt the resolution of domain names to IP addresses, effectively making the web services inaccessible to users.

Zero-Day Vulnerabilities: Attackers often exploit unknown or zero-day vulnerabilities in applications or the network infrastructure as part of their attack strategy. Since these vulnerabilities are not yet known to the vendor, no patch is available, making them an attractive target for attackers.

CDN Cache Bypass – HTTP flood attack bypasses the web application caching system that helps manage server load.

Crafting The Attack Plan

Most modern services no longer run on a single machine in someone’s basement—they are hosted on cloud providers with auto-scaling capabilities and vast network capacity. While this makes them more resilient, it does not make them invulnerable. Auto-scaling has its limits, and cloud networks are shared among millions of customers, meaning attackers can still find ways to overwhelm them.

When planning a DDoS attack, attackers first analyze the target’s infrastructure to identify potential weaknesses. They then select an attack strategy designed to exploit those weak points as efficiently as possible. Different DDoS attack types target different resources and have unique characteristics. Broadly, these attack strategies can be categorized into three main types:

Volumetric Attacks

For volumetric attacks, the attacker’s goal is to saturate the target’s system resources by generating a high volume of traffic. To weaponize this attack, attackers usually employ botnets or compromised systems or even use other cloud providers (paid or fraudulently) to generate a large volume of traffic. The traffic is directed towards the target’s network, making it difficult for legitimate traffic to reach the services. 

Examples: SYN Flood, UDP Flood, ICMP Flood, DNS Flood, HTTP Flood.

Amplification Attacks

Amplification attacks are a cunning tactic where attackers seek to maximize the impact of their actions without expending significant resources. Through crafty exploitation of vulnerabilities or features in systems, such as using reflection-based methods or taking advantage of application-level weaknesses, they make small queries or requests that produce disproportionately large responses or resource consumption on the target’s side. 

Examples: DNS Amplification, NTP Amplification, Memcached Reflection

Low and Slow Attacks

Non-volumetric exhaustion attacks focus on depleting specific resources within a system or network rather than inundating it with sheer volume of traffic. By exploiting inherent limitations or design aspects, these attacks selectively target elements such as connection tables, CPU, or memory, leading to resource exhaustion without the need for high volume of traffic, making this a very attractive strategy for attackers. Attacks, such as Slowloris and RUDY, subtly deplete server resources like connections or CPU by mimicking legitimate traffic, making them difficult to detect.

Examples: Slowloris, R-U-Dead-Yet? (RUDY).

Vulnerability-Based Attacks

Instead of relying on sheer traffic volume, these attacks exploit known vulnerabilities in software or services. The goal isn’t just to overwhelm resources but to crash, freeze, or destabilize a system by taking advantage of flaws in how it processes certain inputs.

This type of attack is arguably the hardest to craft because it requires deep knowledge of the technology stack a service is running on. Attackers must painstakingly research software versions, configurations, and known vulnerabilities, then carefully craft malicious “poison pill” requests designed to trigger a failure. It’s a game of trial and error, often requiring multiple test runs before finding a request that successfully brings down the system.

It’s also one of the most difficult attacks to defend against. Unlike volumetric attacks, which flood a service with traffic that security tools can detect, a vulnerability-based attack can cause a software crash so severe that it prevents the system from even generating logs or attack traffic metrics. Without visibility into what happened, detection and mitigation become incredibly challenging.

Examples: Apache Killer, Log4Shell

Executing The Attack

Now that an attacker has finalized their attack strategy and identified which resource(s) to exhaust, they still need a way to execute the attack. They need the right tools and infrastructure to generate the overwhelming force required to bring a target down.

Attackers have multiple options depending on their technical skills, resources, and objectives:

• Booters & Stressers – Renting attack power from popular botnets.


• Amplification attacks – Leveraging publicly available services (like DNS or NTP servers) to amplify attack traffic.


• Cloud abuse – Hijacking cloud VMs or misusing free-tier compute resources to generate attacks.

But when it comes to executing large-scale, persistent, and devastating DDoS attacks, one method stands above the rest: botnets.

Botnets: The Powerhouse Behind Modern DDoS Attacks

A botnet is a network of compromised devices—computers, IoT gadgets, cloud servers, and even smartphones—all controlled by an attacker. These infected devices (known as bots or zombies) remain unnoticed by their owners while quietly waiting for attack commands.

Botnets revolutionized DDoS attacks, making them:

• Massive in scale – Some botnets include millions of infected devices, generating terabits of attack traffic.


• Hard to block – Since the traffic comes from real, infected machines, it’s difficult to filter out malicious requests.


• Resilient – Even if some bots are shut down, the remaining network continues the attack.

But how do attackers build, control, and launch a botnet-driven DDoS attack? The secret lies in Command and Control (C2) systems.

How a Botnet Works: Inside the Attacker’s Playbook

Infecting Devices: Building the Army

Attackers spread malware through phishing emails, malicious downloads, unsecured APIs, or IoT vulnerabilities. Once infected, a device becomes a bot, silently connecting to the botnet’s network. 

IoT devices (smart cameras, routers, smart TVs) are especially vulnerable due to poor security.

Command & Control (C2) – The Brain of the Botnet

A botnet needs a Command & Control (C2) server, which acts as its central command center.
The attacker sends instructions through the C2 server, telling bots when, where, and how to attack.

Types of C2 models:

• Centralized C2 – A single server controls all bots (easier to attack but simpler to manage).


• Peer-to-Peer (P2P) C2 – Bots communicate among themselves, making takedowns much harder.


• Fast Flux C2 – C2 infrastructure constantly changes IP addresses to avoid detection.

Launching the Attack: Overwhelming the Target

When the attacker gives the signal, the botnet unleashes the attack. Bots flood the target with traffic, connection requests, or amplification exploits. Since the traffic comes from thousands of real, infected devices, distinguishing attackers from normal users is extremely difficult.

Botnets use encryption, proxy networks, and C2 obfuscation to stay online. Some botnets use hijacked cloud servers to further hide their origins.

Famous Botnets & Their Impact

• Mirai (2016) – One of the most infamous botnets, Mirai infected IoT devices to launch a 1.2 Tbps DDoS attack, taking down Dyn DNS and causing major outages across Twitter, Netflix, and Reddit.


• Mozi (2020-Present) – A peer-to-peer botnet with millions of IoT bots worldwide.


• Meris (2021) – Hit 2.5 million RPS (requests per second), setting records for application-layer attacks.

Botnets have transformed DDoS attacks, making them larger, harder to stop, and widely available on the dark web. With billions of internet-connected devices, botnets are only growing in size and sophistication. We will cover strategies on botnet detection and mitigations employed by Azure Front Door and Azure WAF services against such large DDoS attacks.

Wrapping Up Part-1

With that, we’ve come to the end of Part 1 of our Unmasking DDoS Attacks series.

To summarize, we’ve covered:

✅ The fundamentals of DDoS attacks—what they are and why they’re dangerous.

✅ The different categories of DDoS attacks—understanding how they overwhelm resources.

✅ The attacker’s perspective—how DDoS attacks are planned, strategized, and executed.

✅ The role of botnets—why they are the most powerful tool for large-scale attacks.

This foundational knowledge is critical to understanding the bigger picture of DDoS threats—but there’s still more to uncover.

Stay tuned for Part 2, where we’ll dive deeper into well-known DDoS attack patterns, examine some of the biggest DDoS incidents in history, and explore what lessons we can learn from past attacks to better prepare for the future.

See you in Part 2!