Introduction to Active Cyber Defence
Active Cyber Defence (ACD) seeks to reduce the harm from commodity cyber attacks by providing tools and services that protect from a range of attacks.
Our advice & guidance covers a broad range of topics
Resources for individuals and organisations in the UK who have experienced an online scam or cyber attack.
Find a range of products & services from NCSC and certified 3rd party suppliers
Working with industry, government and academia to support the next generation of researchers, students and cyber security professionals
All the latest information to help you keep track of what's happening

The UK continues to be one of the most digitally advanced countries in the world, with our lives being online more than ever before. As this digitisation continues, it is vital that the UK remains able to protect its organisations, business and citizens against cyber crime.
The aim of ACD is to “Protect the majority of people in the UK from the majority of the harm caused by the majority of the cyber attacks the majority of the time.” We do this through a wide range of mechanisms, which at their core have the ability to provide protection at scale.
ACD is intended to tackle the high-volume commodity attacks that affect people’s everyday lives, rather than the highly sophisticated and targeted attacks, which NCSC deal with in other ways.
The ACD programme consists of a number of interventions or real services - each free at the point of use - that perform a particular security service for organisations.