Summary Information systems have inevitably facilitated business and increased profits at the global business scene. Benefits from new technologies bring many risks. The lack of adequate protection of business information systems often leads to loss of valuable data. The paper explores the basic principles and specifications of the protection system, disruption of security systems, multi-layered protection of business systems with a view to adoption of standards that apply to the work. Even though modern technological solutions have a goal to preserve the information systems, none of them is fully secured. Frequent intrusions into the world's most closely guarded information systems are the best proof for that. This paper has a goal to inform the users about aforementioned problems in business information systems. Keywords: Informatics, antivirus programs, business information systems