Dos Vs. DDoS Attacks: What are the Differences?

default image

If you run an online business, you need to be prepared for the dangerous threat of distributed denial of service (DDoS) attacks. DDoS attacks have been making headlines recently with massive assaults against banks, web hosts, and critical infrastructure. Don‘t wait until your own business is targeted – it‘s crucial to understand these attacks and safeguard yourself now.

In this comprehensive guide, I‘ll equip you with everything to know about DDoS and sister denial of service (DoS) attacks. I‘ll explain how they work, compare DDoS vs DoS, and most importantly – provide insider tips to protect your systems as a fellow tech geek. Let‘s dive in!

What is a DoS Attack?

First, a quick primer on standard denial of service (DoS) attacks. The goal of a DoS attack is to temporarily knock a network or server offline by flooding it with traffic. This could be your company website, app server, or core network devices.

DoS attacks are relatively easy to pull off. An attacker sends a nonstop barrage of requests from a single source to overwhelm and crash the target. Common easy DoS methods include:

  • Ping flood – overwhelming a server with ICMP echo request packets.
  • SYN flood – sending continuous SYN packets but never completing connections.
  • Slowloris – slowly filling Apache/IIS connection pools with partial requests.

For example, a DoS using SYN flooding would send constant TCP SYN packets to your server. Your system sends back SYN-ACKs to establish connections, but the attacker never responds. Your connection queues fill up waiting for replies until they hit maximum capacity. Voila, no one else can access your server!

The impact of DoS is typically disruption of service and annoyance versus outright destruction. A single computer can only generate so much traffic. DoS attacks are also easier to trace back to the source IP and shut down.

According to Kaspersky, there were over 8.5 million DoS attacks in 2020 alone. Most attacks are short-lived, lasting under an hour. But the nuisance is real, especially for businesses that promise 24/7 access. DoS attacks also often precede larger assaults.

What is a DDoS Attack?

Distributed denial of service (DDoS) attacks achieve the same end goal as DoS – disrupting access to networks and applications. But DDoS turbocharges the impact by leveraging an army of hijacked devices to overwhelm victims.

Instead of using one source, DDoS attacks rely on botnets – networks of compromised computers and Internet-of-Things devices infected with malware. Criminals build vast botnets by spreading malware through phishing campaigns, exploit kits, and unsecured devices.

When the botnet controller triggers an attack, all the distributed bots simultaneously flood the target with junk traffic. This could entail hundreds of thousands or even millions of unique IP addresses flooding a victim‘s network.

DDoS traffic can quickly overwhelm routers, servers, and upstream ISP links. Massive attacks exceeding 1 Tbps have taken entire data centers offline!

Here are some common high-volume DDoS attack vectors:

  • UDP floods – barrage targets with User Datagram Protocol (UDP) packets.
  • SYN floods – sends endless streams of TCP SYN requests.
  • ICMP floods – overload systems with ICMP Echo Request packets (pings).
  • DNS amplification – exploits DNS servers into overwhelming victims with responses.

According to Netscout, the average DDoS attack size has skyrocketed 782% since 2017 to 37.12 Gbps. As botnets grow in power, we will continue seeing larger and more dangerous attacks.

Major DDoS Attack Types

Beyond brute force volumetric assaults, DDoS attacks also employ other clever techniques:

Protocol Attacks

Protocol or layer 3/4 DDoS attacks send non-standard packets aimed at crashing network devices. For example:

  • SYN flood – rapidly opens connections without closing them.
  • ACK flood – manipulates TCP ACK packets used in handshakes.
  • Fragmented packet attack – sends wrong-sized fragments to crash victims.

These attacks consume firewall and load balancer resources until they are too overwhelmed to function.

Application Layer Attacks

Application layer or layer 7 attacks target web servers and applications specifically. They slam sites with GET and POST commands that mimic legitimate requests. Examples:

  • HTTP request flooding – simple GET/POST requests sent en masse.
  • Slowloris – gradually sends partial HTTP headers to fill Apache/IIS connection pools.
  • DNS amplification – spoofs requests to DNS servers who reply and flood victims.

Application-layer attacks are harder to detect and block since they mimic normal behavior. But they require fewer resources than protocol and volumetric DDoS methods.

Motivations Behind DDoS Attacks

What drives cybercriminals to unleash DDoS mayhem? Some motivations include:

Financial Extortion – Many DDoS groups demand ransom payments in cryptocurrency to call off attacks. Prolexic estimates this extortion economy exceeds $25 billion per year.

Business Disruption – Unscrupulous competitors may DDoS each other‘s services to cause disruptions. Online gambling sites commonly target rivals.

Hacktivism – Activist groups like Anonymous have launched DDoS attacks for political and social causes.

Revenge – Jilted gamers or customers may DDoS companies who they believe wronged them.

Smokescreens – DDoS used as cover to distract IT teams while hackers breach networks via other vectors.

DDoS also requires minimal expertise, encouraging amateur attackers. For as little as $10, anyone can rent a booter/stresser service to overwhelm sites. But the ensuing damages are immense.

Impacts of DDoS Attacks

DDoS attacks have far-reaching technical and business impacts:

  • Service outages – Attacks overwhelm networks, web servers, and infrastructure devices.

  • Lost traffic and sales – With sites down, customers can‘t purchase goods/services.

  • Damaged reputation – Frequent outages hurt consumer trust in the brand.

  • Higher expenses – Extra overhead to purchase DDoS mitigation services.

  • PCI compliance issues – Failures to maintain uptime violate credit card security standards.

According to Radware, the average cost of a DDoS attack exceeds $1 million considering damaged productivity, lost revenue, and mitigation expenses. For ecommerce sites, every minute of downtime easily represents thousands in lost sales.

Protecting Your Business from DDoS Attacks

Now that you understand DDoS and its massive disruptive potential, here are tips to protect your online business:

Monitor Traffic Patterns Closely

Detecting anomalies in traffic levels is key for quick response. Baseline your typical traffic – sudden spikes likely indicate DDoS. For example, a 10x increase in inbound packets per second is highly suspicious. Monitor for unusual IP addresses, requests, geolocations, and packet types too.

Tools like NetFlow, dark web monitoring, and CMS access logs help spot issues early. Don‘t rely on user complaints to alert you – actively watch for shady patterns.

Enable Rate Limiting

Restricting the number of connections per IP address is an easy way to deter abuse. For example, limit IPs to 20 requests per second. Legitimate users won‘t notice, but it stifles DDoS flooding. Implement rate limiting on your routers, application delivery controllers (ADC), and WAF devices.

Distribute Infrastructure Globally

Having all infrastructure in one physical location leaves you vulnerable to catastrophic outages. Distribute servers and data centers globally to withstand localized attacks. Implement Anycast routing to divert traffic across multiple regions.

With distributed resources, you can isolate attack traffic without affecting overall capacity. Use load balancing across nodes to handle spikes gracefully.

Have Detailed DDoS Response Plans

Don‘t wait until under attack to decide how to respond. Create an incident response plan that outlines steps to quickly block sources, divert traffic, enact failover, notify staff, communicate with customers, and more.

Run DDoS simulations to practice execution. Like fire drills, your team needs to know responses instinctively. Streamline processes to minimize business impacts.

Deploy Web Application Firewalls

Reputable web application firewall (WAF) solutions like Cloudflare, Imperva, and Akamai actively filter DDoS traffic while allowing legitimate users through. Configuring custom threat detection rules enables identifying and stopping zero-day attacks too.

WAFs also execute rate limiting, IP blacklisting, deep packet inspection, and geoblocking to repel DDoS. Invest in a cloud-based WAF that scales easily to absorb massive attacks.

Consider DDoS Mitigation Services

For truly monstrous DDoS attacks exceeding 50 Gbps, specialized mitigation services may be your best bet. Providers like Akamai, Radware, and Cloudflare operate global networks that can absorb incredible capacity.

Route your traffic through scrubbing centers during attacks. Evaluate the reputation and mitigation capacity when choosing providers. Implement failover to these services when on-premise defenses are overwhelmed.

Keep Software Patched

Unpatched vulnerabilities in operating systems and applications often get exploited to build botnets. Leverage tools like automation and vulnerability management to stay on top of patching. Eliminate end-of-life software prone to unfixable risks.

DoS vs. DDoS Attacks

While denial of service (DoS) and distributed denial of service (DDoS) attacks share the same goal of disrupting services, there are distinct differences:

Factor DoS Attack DDoS Attack
Traffic source Single computer/IP address Thousands of unique IP addresses in a botnet
Attack size Up to 1 Gbps Commonly exceeds 50 Gbps
Persistence Usually short bursts Sustained over a longer period
Detection difficulty Easier to detect lone source Harder to blacklist all bot IPs
Impact Annoyance/disruption Massive destruction
Mitigation Block single IP Complex coordinating mitigation across infrastructure

To summarize, DDoS is DoS on steroids. The distributed nature of DDoS allows it to wreak much greater havoc on targets. But the defensive strategies are similar – identification and restriction of malicious traffic.

Closing Thoughts

I hope this guide has helped shed light on the menacing threats of DDoS and DoS attacks. As our world grows more connected, these attacks will only become bigger and more sophisticated. Don‘t wait until your own business suffers outages to take action.

Monitor your traffic vigilantly for anomalies. Have mitigation game plans ready. Employ layered defenses like firewalls, WAFs, rate limiting and traffic diversion. With proactive protection, you can confidently thrive online without fear of DDoS disruptions.

Stay safe out there and let me know if you have any other security concerns!

Written by