Denial-of-Service Attacks
Learn how floods of traffic knock services offline.
What a DoS Attack Is
A DoS (Denial-of-Service) attack tries to make a service unavailable to legitimate users by overwhelming it. Unlike attacks that steal data, a DoS targets availability, the third pillar of the CIA triad.
By flooding a server or network with more traffic or requests than it can handle, the attacker exhausts its resources until real users cannot get through.
DoS vs DDoS
A plain DoS comes from a single source. A DDoS (Distributed Denial-of-Service) comes from many sources at once, often thousands, making it far harder to stop.
Blocking one attacking IP is easy; blocking traffic from tens of thousands of scattered addresses, many of them innocent hijacked machines, is the real challenge that makes DDoS so dangerous.
All lessons in this course
- Spoofing and On-Path Attacks
- Denial-of-Service Attacks
- Social Engineering and Phishing
- Building Practical Mitigations