The exact behavior is up to the DM but enemies can very well attack you.
On a failed save, the creature's Intelligence and Charisma scores become 1. The creature can't cast spells, activate magic items, understand language, or communicate in any intelligible way. The creature can, however, identify its friends, follow them, and even protect them.
The rules do not specify the target creature's exact behavior and assuming the target is NPC controlled by the DM they will have the final word in what the creature does.
That being said feeblemindfeeblemind lowers targetstarget's intelligence score to 1 which is comparable to many creatures, commonly beasts in the monster manualMonster Manual. Due to this, I would say it is reasonable for the target to act similarly to how an animal or a beast would act in any given scenario, including protecting its friends (as mentioned by the spell) and attacking, or running from enemies it perceives as a threat.