The EU’s ‘cyber security’ agency, ENISA, today published a comprehensive study on the botnet threat (networks of ordinary computers controlled by cybercriminals), and how to address it. The report looks at the reliability of botnet size estimates and makes recommendations for all groups involved in the fight against botnets. Alongside the main report the agency sets out the top 10 key issues for policymakers in ‘Botnets: 10 Tough Questions’. Botnets are networks of computers used without their owner’s knowledge for cybercrime such as spamming and the automated theft of valuable data such as credit card information and even politically motivated cyberattacks. The study will be launched at a conference in Cologne on Wednesday 9 March.