Explain a DDoS attack

Explain how a Distributed Denial of Service (DDoS) attack is carried out and the impact it has on a target organisation. [5 marks]

Mark scheme (5): 1 mark each, max 5.

• Attacker infects many computers with malware to form a botnet [1]
• The compromised machines are controlled remotely by the attacker [1]
• All bots are instructed to send huge volumes of requests/traffic to the target server simultaneously [1]
• The server's bandwidth or processing capacity is exhausted [1]
• Legitimate users cannot access the service / website goes offline [1]
• Allow: financial loss / reputational damage / lost transactions / SLA breach as impact points.