What is the best way to keep passwords configurable, without having them too easily available to the casual human reader?

Question

I have a database that many different client applications (a smattering of web services, some java apps and a few dot net applications) connect to. Not all of these are running on windows (Sadly, otherwise it would make this an easy answer question with just enabling windows authentication for database connections). At the moment, the passwords are stored in various configuration / properties files lying around the systems. Ideally, only the support staff have access to the servers where the files are running, but if someone else gains access to one of the servers, they would have enough database permissions to get a fair whack of data as it stands now.

My question then, What is the best way to keep the passwords configurable, without having it too easily available to the casual human reader?

Edit Just to clarify, DB server is Windows Server 2003, running MSSQL 2005.

PS: I don't see any questions that this duplicates, but if there are, please feel free to close this one.

Answer 1

I'm assuming you want to hide the passwords from casual observers. If they were evil, steely eyed observers with access to all the source code on one of the machines that connects, then they can get the password with a bit of reverse engineering.

Remember that you do not need to use the same protection for each different client. A few steps:-

1. Create different database accounts for different systems that access your database
2. Limit access on the database to only what they need using your inbuilt database GRANTs
3. Store a triple DES (or whatever) key inside a password manager class on your database. Use this to decrypt an encrypted value in your properties file.

We have also considered having the application prompt for a pass-phrase on startup but have not implemented this as it seems like a pain and your operations staff then need to know the password. It's probably less secure.