Cyber attacks are no longer a problem only large enterprises face. Today, businesses of every size are targeted by increasingly sophisticated online threats, including DDoS attacks. These are distributed denial of service attacks that can overwhelm websites, disrupt operations, and damage customer trust within minutes.
Understanding how these attacks work is essential for anyone responsible for protecting a business online. This guide explains what a DDoS attack is, how attackers launch them, the warning signs to watch for, and the best ways to prevent disruption before it happens.
Key takeaways
- A DDoS attack floods a system with traffic to make it unavailable.
- Attackers often use large networks of infected devices called botnets.
- Businesses can suffer downtime, revenue loss, and reputation damage.
- Modern DDoS attacks are becoming faster and more automated.
- Prevention requires layered cyber security protection, monitoring, and training.
What is a DDoS attack?
A DDoS attack (distributed denial of service attack), is a cyber attack designed to overwhelm a website, server, or network with massive amounts of internet traffic.
The goal is to force systems offline so legitimate users cannot access them.
Unlike a normal denial of service attack (DoS), a DDoS attack uses multiple devices simultaneously.
Featured snippet definition
| Term | Definition |
|---|---|
| DDoS attack | A distributed denial of service attack is a cyber attack where multiple compromised devices flood a target system with traffic, causing disruption, downtime, or complete service failure. |
DoS vs DDoS (quick differences)
- DoS usually comes from one source.
- DDoS comes from many sources (often thousands).
DDoS attacks are harder to block because traffic looks distributed.
How does a DDoS attack work?
Most DDoS attacks rely on something called a botnet.
What is a botnet?
A botnet is a network of infected devices controlled remotely by cyber criminals.
These devices can include:
- Computers.
- Smartphones.
- IoT devices.
- Security cameras.
- Routers.
- Smart TVs.
Many device owners never realise their hardware has been compromised.
Step-by-step breakdown
- Attackers infect devices with malware.
- Devices become part of a botnet.
- The attacker sends commands to the botnet.
- Thousands of devices flood a target with requests.
- The target server crashes or slows dramatically.
Why DDoS attacks are difficult to stop
With traffic coming from many locations, blocking a single IP address does not solve the issue.
Modern attacks can also mimic legitimate traffic, making detection harder.
According to Cloudflare, some attacks now exceed several terabits per second, making them among the largest cyber threats organisations face.
Types of DDoS attacks
Not all DDoS attacks work the same way.
Volumetric attacks
These attacks attempt to consume all available bandwidth.
Common examples:
- UDP floods.
- ICMP floods.
- Amplification attacks.
Protocol attacks
Protocol attacks target weaknesses in network infrastructure.
Examples include:
- SYN floods.
- Ping of death.
- Fragmentation attacks.
Application layer attacks
Application layer attacks target websites and applications directly.
Examples:
- HTTP floods.
- API abuse.
- Login request flooding.
DDoS attack types comparison
| Attack type | Target | Goal | Difficulty to detect |
|---|---|---|---|
| Volumetric | Bandwidth | Saturate network traffic | Medium |
| Protocol | Servers/network devices | Exhaust resources | Medium |
| Application layer | Websites/apps | Disrupt user experience | High |
Real-world DDoS attack examples
GitHub DDoS attack
GitHub experienced one of the largest DDoS attacks ever recorded. The attack peaked at 1.35 tbps and lasted around 20 minutes before being mitigated using traffic scrubbing services.
Dyn DNS attack
The Dyn DNS attack disrupted access to major sites like Twitter, Netflix, Reddit, and Spotify. Attackers used compromised IoT devices in the Mirai botnet, highlighting how vulnerable connected devices can become when poorly secured.
Original insight: Many businesses still assume DDoS attacks only target large corporations. In reality, SMBs are increasingly targeted because they often lack enterprise-level protection and response capabilities.
What happens during a DDoS attack?
A successful DDoS attack can create serious operational problems.
Common business impacts:
- Website outages.
- Lost revenue.
- Poor customer experience.
- Reduced employee productivity.
- Service disruption.
- Brand reputation damage.
The financial cost
Downtime-related incidents can cost organisations thousands of pounds per minute depending on industry and scale.
For ecommerce businesses, even short outages can significantly impact sales and customer trust.
Signs your business may be under attack
Early detection matters.
Warning signs include:
- Sudden traffic spikes.
- Slow website performance.
- Frequent server crashes.
- Connectivity issues.
- Unusual traffic from specific regions.
- Increased timeout errors.
Traffic spikes are not always malicious as marketing campaigns and product launches can increase website traffic naturally. The difference between the two lies in traffic patterns and intent.
How to respond to a DDoS attack (incident playbook)
Immediate actions
- Confirm the incident with traffic monitoring tools.
- Notify your hosting provider and mitigation vendor.
- Enable rate limiting, WAF rules, and traffic scrubbing.
- Reduce non-essential functionality to preserve availability.
- Communicate clearly with customers about service status.
- Collect logs for investigation and recovery.
After the attack
- Review what worked and what failed.
- Update incident response plans.
- Strengthen monitoring thresholds.
- Use learnings to improve prevention.
How to prevent DDoS attacks
No solution guarantees complete protection, but strong preparation dramatically reduces risk:
Use DDoS protection services
Cloud-based DDoS mitigation providers can absorb malicious traffic before it reaches your systems.
Implement web application firewalls (WAFs)
A WAF helps filter malicious traffic targeting websites and applications.
Monitor network traffic continuously
Real-time monitoring helps identify suspicious behaviour quickly.
Businesses should monitor:
- Traffic spikes.
- Unusual request patterns.
- Failed login attempts.
- Geographic anomalies.
Build redundancy into infrastructure
Load balancing and distributed hosting reduce single points of failure.
Strengthen employee awareness
Employees often overlook security hygiene, regular cyber awareness training helps teams:
- Recognise suspicious activity.
- Report incidents quickly.
- Reduce broader cyber security risks.
Businesses that combine technical controls with human awareness typically recover faster and experience lower long-term risk exposure.
DDoS mitigation best practices (security checklist)
| Best practice | Purpose |
|---|---|
| Traffic filtering | Blocks malicious requests |
| Rate limiting | Prevents overload |
| CDN usage | Distributes traffic globally |
| Multi-region hosting | Reduces outage risk |
| Incident response planning | Improves recovery speed |
How AI is changing DDoS attacks
Modern attackers increasingly use automation to deploy attacks faster and craft traffic that looks more legitimate.
AI-driven detection systems can help defenders identify abnormal patterns sooner, but only when monitoring is properly configured.
Why small businesses should take DDoS attacks seriously
Attackers often see smaller organisations as easier opportunities.
Common SMB weaknesses
- Limited security budgets.
- Outdated infrastructure.
- Weak monitoring.
- Insufficient staff training.
- No incident response process.
Even a short outage can create lasting consequences for customer trust and operational continuity.
Conclusion
Understanding what a DDoS attack is the first step toward protecting your business from disruption. These attacks are designed to overwhelm systems, interrupt services, and create costly downtime. As attacks become larger and more automated, businesses of all sizes need stronger visibility, monitoring, and response strategies.
The three most important takeaways are:
- DDoS attacks use massive traffic volumes to disrupt services.
- SMBs are increasingly targeted due to weaker protection.
- Prevention requires both technical controls and employee awareness.
Want to strengthen your organisation’s cyber resilience? Explore our cyber security awareness solutions and discover how proactive training can help reduce risk, improve incident response, and support long-term business protection.
FAQs about DDoS attacks
What is the difference between a DoS and DDoS attack?
A DoS attack comes from a single source, while a DDoS attack uses multiple compromised devices simultaneously, making it more powerful and harder to stop.
Can small businesses be targeted by DDoS attacks?
Yes. Small businesses are common targets because attackers often view them as having weaker security defences.
How long do DDoS attacks last?
Some attacks last only minutes, while others continue for days depending on attacker resources and mitigation capabilities.
Are DDoS attacks illegal?
Yes. Launching a DDoS attack is illegal in most countries and can result in severe criminal penalties.
Can firewalls stop DDoS attacks?
Traditional firewalls alone are usually insufficient. Businesses often require dedicated DDoS mitigation tools and cloud-based protection services.
