Mechanically, it can't
Similar to the argument here, the Mage Hand has no stat block, it has no AC, no HP, so it doesn't make much sense to consider it attackable. Thinking in game terms, it's neither a creature nor an object, which are the usual targets for spells or attacks.
As a comparison, check Bigby's Hand:
The hand is an object that has AC 20 and hit points equal to your hit point maximum. If it drops to 0 hp, the spell ends. It has a Strength of 26 (+8) and a Dexterity of 10 (+0). The hand doesn't fill its space.
So, if the "thing" created by a spell is supposed to be targetable, something on these lines should be written.
As the DM would have to "make up" an AC and HP for it, as well as the consequences for its HP reaching zero, it's clearly intended that it can't be a target, since Spells only do what they say. Further indication of it is that the conditions when the spell ends are clearly defined:
The hand lasts for the duration or until you dismiss it as an action. The hand vanishes if it is ever more than 30 feet away from you or if you cast this spell again.
Meaning that reaching 0 HP shouldn't mean it would vanish (as the only written conditions for vanishing are these).
Now, rethinking my answer, there is one thing: the lack of AC and HP doesn't mean something can't be "targeted". A creature could decide to "attack" the air, or the water in a river or the ground, with no effects whatsover. The same could be ruled to the Mage Hand - creatures could try to target it and attack it, it just would be the same as attacking nothing.
Now, would they? In most situations, I wouldn't rule that my creatures decide to attack the hand, since wasting their actions for nothing would make the cantrip stronger than it should be.
So, even though it is technically possible that the creatures choose to attack it, usually they shouldn't, mainly from metagaming/balance perspective.