Assessment of production systems security from the perspective of external and internal IT auditor

This diploma thesis focuses on familiarizing the reader with the field of IT audit performed in companies in order to test and assess the quality of IT management, security, risks and quality of processes related to the use of information systems and technology in the audited environment. The introductory part of the thesis is devoted to theoretical introduction to audit and its historical development. Next the thesis introduces methodological standards and working frameworks, which can be used in IT audit or can be used as a basis for creating own IT audit methodology. Higher attention is put in the COBIT methodological framework issued by the international organization ISACA that is used in a practical demonstration of the internal IT audit in this thesis.The main part of the thesis is devoted to the description of procedures of external and internal IT auditor including description of controls, security risks and areas, which the auditor focuses in performing his work. The theoretical description is subsequently supported by practical examples of both IT audits in real companies performed by the author of the thesis.The final part of the thesis compares both mentioned IT audits in terms of audit scope, audit procedures and audit conclusion.