22.7.2. Share-Level Security
With share-level security, the server accepts only a password without an explicit username from the client. The server expects a password for each share, independent of the username. There have been recent reports that Microsoft Windows clients have compatibility issues with share-level security servers. Samba developers strongly discourage use of share-level security.
security = sharedirective that sets share-level security is:
[GLOBAL] ... security = share ...