The cyber kill chain is a phase model for targeted attacks: from reconnaissance via weaponisation, delivery, exploitation and installation to command-and-control and the actual objective — such as data theft or encryption.
The central message is optimistic: an attack is a chain, and the defender only has to cut it in one place. Every phase offers its own detection and defence points.
The phases and their countermeasures
Early in the chain, prevention and hygiene act: attack surface management against reconnaissance, email and web protection against delivery, patching and hardening against exploitation. From installation onwards, EDR and application controls take over; DNS filters and NDR catch command-and-control traffic; segmentation, privilege concepts and backups limit the impact.
Read in a modern way, the chain is not a rigid sequence — real attacks jump, repeat phases and run in parallel. As a mental model for defence in depth it remains valuable: covering every phase with at least one control forces attackers to succeed several times instead of once.
Using the model practically
- Map controls to phases: where are we strong, where blind?
- Reconstruct incidents along the chain: how far did the attacker get — and why?
- Balance investments: not everything into prevention, enough into detection and containment.
- Refine with MITRE ATT&CK when technique-level precision is needed.