That's probably what it is.

Lunar soil reflects very strongly when viewed 180 deg away from the sun. I.e, if you're on the ground, the soil is a lot brighter in the direction away from the sun. If you're in the air, then the anti-solar point will be especially bright -- with your own shadow right in the middle of it.

I think the theory on the moon is that you get lots of little specular reflections off of the microscopic, angular, glassy fragments in the regolith (e.g., like ice crystals in clouds).

That we see one on Mars tells us something about soil properties, I'm sure. But I have no idea if that is a bright or dim glory compared to what you'd see in a similar position above the Moon, or above a cirrus cloud on Earth for that matter. Given that the soil there is very dark, it wouldn't take much for a bit of a halo to show up.