Integrity is the second of the three objectives of information security. All three, and their relationship to security and to risk management, are depicted in Figure 1.
Protecting information integrity goes beyond preventing unauthorized viewing. It requires the implementation of policies, processes, and technology that prevent or detect the unauthorized modification of data. Threats against integrity are similar to those that may compromise confidentiality. But there are additional steps managers can take to ensure data is not changed without proper authorization.
- Enforce Least Privilege - Users should have change access only where necessary to perform their day-to-day tasks.
- Separation of Duties - No single employee should be able to perform all tasks associated with a single transaction. For example, an employee in Payroll shouldn't be able to:
- Create an employee account
- Enter a manual payroll check
- Approve the manual payroll check
- Pick up the check for the named employee
Any one of the first three tasks moved to another employee will significantly reduce the risk of fraud. Separation of duties is based on the belief that the probability of two or more employees colluding to perform an unauthorized act is much less than a single employee performing the same act alone. - Rotation of Duties - One of the best ways to prevent or detect unauthorized changes to data is rotating employees through different roles. If an employee knows someone else will have access to the work she's done, she'll be less likely to perform an unauthorized or illegal act.
- Application-only Data Access - User access to data should be restricted to application interfaces. Direct database access should be allowed only for those directly responsible for database health, such as database administrators. Even then, managers should implement controls that monitor database management activities.
