What determines the winner of a virtual PF battle?

I've progressed far enough into the game where I was eligible for virtual battles. Everything seemed pretty straight forward for a while. You "battle" with other PFs and gain points for successful attacks and defenses. Generally, the higher the numbers, the more likely you're able to succeed.

In the beginning, it was almost guaranteed that you would always win attacks and lose on defenses since we tend to build up the combat unit more than the security team. The numbers were generally higher on attack and lower on defense. At higher rankings, I've been winning a lot of defenses, even though I had smaller numbers. There's obviously some randomization going on and the higher the numbers might make it more likely to win. Nowadays, I'm almost never winning anymore since most players have apparently cheated

How did my 450 strong, Level 122 team lose to a Level 0, empty base?

What determines the winner?
How does the Capability number factor in?
How does the Durability number factor in?
How does the Defense Level/Development Grade factor in? Does having a nuke affect the outcome?

All of my forces are generally S+ or S++. I have all of the offline weapons researched and most of the online weapons that can be used by my security teams. My security settings is the advanced settings enough to get the highest level possible. Mother base is fully upgraded while I have two fully upgraded FOBs, one almost fully upgraded FOB, and one more with a couple of platforms. Apparently I've gotten high enough into the rankings that nearly every single player out there has cheated.