We're considering to enable our >10 suppliers (mainly from China) to input/edit/view data via an unified interface. The preferred way is to use the same windows-based .NET/MSSQL application as used internally.
As the application needs a direct database connection, my idea is to grant all suppliers access to a server at our site via terminal services. But there are concerns about the security of this approach, so that the current plan is to develop a web interface to the application (costly) or continue to use excel/txt/word/pdf for data submission (well...).
In deep detail, my approach would consist of:
Windows Server 2003, SQL Server 2005, the application
windows update set on auto
Terminals Services, granted to individual users
directly start application (group policy), auto log-off after termination
adjust file system ACLs to prevent:
- any file writes (except e.g. profile files)
- execution of taskmgr, cmd, ftp, telnet, (explorer.exe?)
registry ACLs should be ok
change RDP port
auditing enabled (group policy), report events via e-mail to admins:
- execution of cmd, taskmgr, etc. (all users, including system/admin/...)
- change of security permissions
- connected via crossover ethernet
completely firewalled (inbound)
synchronize every 5 minutes:
- open LAN interface
- synchronize files via network share
- synchronize database via SQL Server replication (some tables inbound, many outbound)
- close LAN interface
backup and history backups (as the external server has the master copy of the applications database)
As I use a similar approach in my department (web- instead of terminal services), I have no objections to the setup. The only practicable attack I'm concerned with, is a breach of in the application itself, which could lead to a compromise of application specific data (over all suppliers).
Nevertheless, as I have to convince a bunch of people favouring the excel approach, I'd like to hear your thoughts.