Cybersecurity is a global issue with local impact. When cyber security breaches occur, it impacts on society at all levels: Users lose trust in digital platforms, companies lose money, and public institutions are discredited. Over the last years, cybersecurity as a concept has changed significantly and has become a broad area covering for example crime, espionage, privacy inva- sions, and technical solutions for prevention of attacks on users, individuals as well as industry/companies. Along with this, privacy has become a central element in the discussion mirroring the fact that users have become much more aware of the consequences of disclosure of private data to the online businesses and market. On the supplier side new as old web- and cloud- based services are aware that they are reliant on the trustworthiness they can provide to the customers. Trust is therefore an underlying element central for any detection, managing or prevention technologies being developed within the field of cybersecurity and privacy. This special issue has seven different contributions addressing aspects of the broad area of cybersecurity. 1. On the Use of Machine Learning for Identifying Botnet Network Traffic 2. Practical Attacks on Security and Privacy Through a Low-Cost Android Device 3. Comparative Investigation of ARP Poisoning Mitigation Techniques Using Standard Testbed for Wireless Networks 4. Information Security Risk Assessment of Smartphones Using Bayesian Networks 5. Digital Forensic Investigations: Issues of Intangibility, Complications and Inconsistencies in Cyber-Crimes 6. Factors Influencing the Continuance Use of Mobile Social Media: The Effect of Privacy Concerns 7. Confidentiality in Online Social Networks; A Trust-based Approach