BSI-100-2: S 4.13: Careful allocation of identifiers: Every GID must be unique
Information
Every log-in name, every user ID (UID) and every group ID (GID) must be unique. Even after deletion of a user or a group, the log-in name and the UID or GID should not be reassigned for a certain period of time. On networked systems, steps must be taken to ensure that it is not possible for the same user names and IDs to be assigned elsewhere on the system more than once. Safeguard Catalogues: S 4: Hardware and software S 4.13: Careful allocation of identifiers