I loop my sling through one of the two slits in the MOE stock. It's very secure.
I like using the lower slit because I prefer not to loop around the butt plate. I have this set up on the AR-15 I assembled myself. I like it because it keeps it 2-point sling simple.The other option I can think of is to swap stocks to the CTR stock that has a built in QD mount. I just don't see the point in spending another $80.
The third option is to install a
Troy Pro Grade Rifle Sling Adapter. It clamps onto the buffer tube. It comes with a QD sling swivel that can be fixed to either side.