for access the DB the user needs to be added to the SQL Logins and he needs db_datareader rights to the database (or it there is somethink to writhe / change db_datawriter)
To grant access to the Integration Services service
Run Dcomcnfg.exe. Dcomcnfg.exe provides a user interface for modifying certain settings in the registry.
In the Component Services dialog, expand the Component Services > Computers > My Computer > DCOM Config node.
Right-click Microsoft SQL Server Integration Services 11.0, and then click Properties.
On the Security tab, click Edit in the Launch and Activation Permissions area.
Add users and assign appropriate permissions, and then click Ok.
To grant access to the Integration Services service
Run Dcomcnfg.exe. Dcomcnfg.exe provides a user interface for modifying certain settings in the registry.
In the Component Services dialog, expand the Component Services > Computers > My Computer > DCOM Config node.
Right-click Microsoft SQL Server Integration Services 11.0, and then click Properties.
On the Security tab, click Edit in the Launch and Activation Permissions area.
Add users and assign appropriate permissions, and then click Ok.
Repeat steps 4 - 5 for Access Permissions.
Restart SQL Server Management Studio.
Restart the Integration Services Service.