Front Bear Hug

If someone attacks in a rear bear hug, the first thing you want to do is lower your weight to prevent them from being able to pick you up. Getting picked up can be bad because they usually smash you down on the pavement.

Step back with one leg to drop your weight and you are in position to send a few knees to your attacker's groin or stomach. Make sure you are breathing (yelling is better) as you attack with each strike.

A few consecutive blows may free you or at least loosen the hold. Then using your palms, drive them into his ribs (floating ribs) at each side.

At that time you should decide whether to follow up with strikes to the face, depending on what kind of danger you feel you are in. Your arms may be free or pinned, but in both situations you should use them to steady yourself by holding your opponent in order to deliver more accurate strikes and to push him away once he is weakened by them.

As stated earlier, the worst scenario here is that they pick you up and slam you. So it is important to react quickly and decisively. See self defense.