"opens another executable"? I have no idea what you mean with that. The Origin version starts a launcher program exactly for security reasons, since that launcher checks your Origin login. I have no idea how/why you think this is in any way a security bug or a vulnerability. It doesn't open "a random executable on your disk", it launches one specific executable on your disk. Or are they actually launching wrong games? Your explanation is really unclear.
The fix for your issue is probably disabling the Origin In Game feature, by the way, since it doesn't seem to be compatible with the C&C games. Check the sticky "How to run older Command & Conquer titles" thread at the top of the forum.
But hey, Command & Conquer 1, Red Alert 1 and Tiberian Sun are all freeware, so if you want to get rid of all that, get the freeware versions and use those. You can find them here:
Command & Conquer 1:
Red Alert 1:
Tiberian Sun:
Thanks for the tip to get the freeware however. Will probably download those.
