Written by Emma Mouncey
University of Portsmouth
DoS (Denial-of-Service) Attacks are malicious attacks aiming to disrupt a server or network using a computer.
DDoS (Distributed Denial-of-Service) Attacks are the same as DoS attacks but use multiple systems. These can be remotely used computers compromised through malware.
How DDoS attacks work :
DDoS attacks can either be many different individuals working together to overload a system or An individual using botnets which are computers hacked through malware and operated as a virtual machine.
- Overloaded network layer – hardware or software failure due to overloading the network capacity, ie WiFi bandwidth.
- Overloaded application layer – Overloading the system with too many requests and applications, ie asking the processor to do too much work.
(This takes less resources for the attacker)
To render a service unusable.
- Users will not be able to use or view the site.
- Customer complaint.
- Cannot retrieve site data.
- Loss of productivity.
- Reputational damage as there is a potential for not being able to fulfill contracted roles.
- Business functions are inaccessible
In 2022 Microsoft mitigated over 520,000 unique DoS attacks from their global infrastructure.
Azure Network Security Team, 2023
How to spot a DDoS Attack:
- Sites are running slower than usual.
- High number of requests from the same IP address.
- Customers cannot access your site.
- Error 503 warning appears – this shows a server that is overloaded or temporarily down for maintenance.
How to protect your business:
- Know your weaknesses (ie your bandwidth and capacity size) and plan what to do in this instance. This includes contacting customers.
- Invest in a business grade router. This will increase bandwidth and be aware of the maximum capacity.
- Buy a Web Application Firewall – this identifies DDoS tools and protects your website.
Why your small business is targeted:
- Smaller businesses do not usually have large bandwidths to hold large volumes of traffic so are easier to overload as it would need less resources to overwhelm.
- DDoS prevention software can be expensive so smaller businesses do not have them.
- Do not have a high budget to implement sophisticated cyber security systems.