Write access to production program libraries presents the greatest risk when granted to a new member of the system development staff. Production program libraries contain executable code that runs on live systems and supports critical business functions. Write access allows a user to modify or delete existing programs, or add new programs to the library. If a user were to make unauthorized or erroneous changes to production programs, it could cause serious disruptions, errors, or security breaches in the organization's operations.
Therefore, write access to production program libraries should be restricted to authorized personnel only, and subject to strict change management controls.