Migrating to the cloud introduces immense benefits for companies and individuals in terms of efficiency and costs. With respect to security, the effects are quite diverse, but it is a common perception that using cloud services impacts security in a positive manner. Opinions, however, diverge many times even on defining who is responsible for ensuring the security of cloud resources.Covering IaaS, PaaS and SaaS, first the security of the infrastructure is discussed: hardening and configuration issues as well as various solutions for authentication and authorization alongside identity management that should be at the core of all security architecture. This is followed by some basics regarding legal and contractual issues, namely how trust is established and governed in the cloud.The journey through cloud security continues with understanding cloud-specific threats and the attackers’ goals and motivations as well as typical attack steps taken against cloud solutions. Special focus is also given to auditing the cloud and providing security evaluation of cloud solutions on all levels, including penetration testing and vulnerability analysis.The focus of the course is on application security issues, dealing both with data security and the security of the applications themselves. From the standpoint of application security, cloud computing security is not substantially different than general software security, and therefore basically all OWASP-enlisted vulnerabilities are relevant in this domain as well. It is the set of threats and risks that makes the difference, and thus the training is concluded with the enumeration of various cloud-specific attack vectors connected to the weaknesses discussed beforehand.