The development of information systems today is followed by an increase in attacks on information systems. This is due to the growing number of information systems that store sensitive data for users such as telephone numbers, population identification numbers, birth dates and even bank account numbers. These data are very prone to be misused by irresponsible parties. So security is one of the factors that must be the main consideration in the development of information systems. This research studies various attack techniques on information systems. To facilitate identification, these attacks are classified based on the components of the information system. The results of this study indicate that there are attacks aimed at each component of the information system. At the end of this study provides suggestions to minimize the impact of attacks and to improve information system security.