These threats range from the intentional theft or destruction of data to the acquisition of information through more subtle measures, such as inference. The improper release of information from reading data that was intentionally or accidentally accessed by unauthorized users. Securing data bases from unauthorized access is more difficult than controlling access to files managed by operating systems. This problem arises from the finer granularity that is used by data bases when handling files, attributes, and values. This type of problem also includes the violations to secrecy that result from the problem of inference, which is the deduction of unauthorized information from the observation of authorized information.
Inference is one of the most difficult factors to control in any attempts to secure data.
Because the information in a data base is semantically related, it is possible to determine the value of an attribute without accessing it directly. Inference problems are most serious in statistical data bases where users can trace back information on individual entities from the statistical aggregated data. The improper modification of data. This threat includes violations of the security of data through mishandling and modifications by unauthorized users. These violations can result from errors, viruses, sabotage, or failures in the data that arise from access by unauthorized users.