Could a program "steal" your private data secretly, if so h

[rv31]

So i have a program that connects to various well known websites to gather data, bit like agthering the state of the weather for example, the data is shown on a graph on my pc in real-time and updated at very regular intervals.

Now in this program you have to add some configurations and private data (trade secrets if you like) that will determine the data sent back to me. These "trade secrets" data could be of use to competitors etc...

Could this program send this information to some IP without will it was already connected online without my knowing, in other words spyware....

If so how would i block it from doing so?

I guess a software firewall would be the only answers as i could see what outgoing connections are being made?

Still if you really wanted to i am sure you could bypass the firewall, process injection etc,,, i don't think i am being unrealistic here, any ideas?

[GrofLuigi]

Through firewall control you let it connect only to the known site (weather site).

If it is a well known program, you could google about its behavior...

If you need to know more, you would have to disasemble it...

GL

[DigeratiPrime]

The Windows Firewall in XP can only control incoming connections, if you want to restrict software from opening connections you need a 3rd party firewall.

The Windows Firewall in Vista can block 3rd party software from opening connections but default allows all outgoing traffic.

The Windows Firewall in 7 will alert the first time a 3rd party software tries to open a connection with choices based on network locations.

If you're concerned about DLL Injection you should consider Vista as it has ASLR and UAC which will protect processes from each other.