Even for bad poker sites they are using HW RNGs. I worked for a hybrid meat space/online casino and we were using IDQ cards. Except when we were not. Owner got

Even for bad poker sites they are using HW RNGs. I worked for a hybrid meat space/online casino and we were using IDQ cards. Except when we were not. Owner got squirrely and went for bottom dollar to implement a stand alone version of a carefully engineered system I had developed. The developers ended up using /dev/random instead of at least making a 1 gig rng lookup table. Also the ticketing system was unencrypted so you could print whatever you on a barcode and feed it to the redemption machine to clean it out. Also the games were not tested statistically. Literally a guy sat there and played games until it "felt" right. I tried to help them out, but eventually I washed my hands of everything and walked away. Too many weird things going on. From talking to others in the industry it is not that different elsewhere. TL;DR - If you do work for casinos be ready to walk away when things get weird.