not sure which provider you're using but here's a some security considerations for database access in Sync FX:
EXECUTE permissions on all the stored procedures that Sync Framework uses to read and write to metadata tables and base tables.
SELECT, INSERT, UPDATE, and DELETE permissions for metadata tables and any base tables that will be updated during a synchronization session.
When you provision SQL Server databases that use SqlSyncProvider, be aware of the following permissions requirements for provisioning:
CREATE TABLE permissions to enable creation of the metadata tables: scope_info and scope_config, and the tracking tables that are created for each base table.
ALTER TABLE to add triggers to the base tables.
CREATE PROCEDURE permissions to create the procedures that Sync Framework requires.
SELECT and INSERT permissions for scope_info and scope_config tables.
SELECT permissions for base tables.