I have written a program that is sort of an unofficial, standalone plugin for an application. It allows customers to get a service that is a lower priced alternative then the vendor-owned one. My program is not illegal, against any kind of TOS, and is certainly not a virus, adware, or anything like that. That being said, the vendor of course is not happy about me taking his competition, and is trying to block my application from running.

He has already tried some tactics to stop people from running my app alongside his. He makes it so if it is detected, his app throws a fake error.

First, he checked to see if my program was running by looking for an open window with the right title. I countered this by randomizing the program title at startup.

Next, he looked for the running process name. I countered this by making the app copy itself when it is started as [random string].exe and then running that.

Anyways, my question is this: what else can he do to detect if my program running? I know that you can read window text (ie status bar, labels). I'm prepared to counter this by replacing the labels with images (ugh, any other way?).

But what else is there? Can you detect what .dlls a program has loaded? If so, could this be solved by randomizing the dll names before loading them?

I know that it's possible to get a program's signature in memory and track it that way (like a virus scanner), but the chances of him doing that probably aren't good because that sounds pretty advanced.

Even though this is kinda crappy of him to be doing, its kind of fun. It's like a nerdy fist fight.

EDIT: When I said it's a plugin, that is just the (incorrect) term I used. It's a standalone EXE. The "API" between my program and the other is mine is simply entering data into the controls (like textboxes, etc).