Behold! what you have often seen but probably didn’t knew what it was. That’s Lunar Corona.
Lunar coronae are much more familiar than those around the sun. They are seen when the clouds are thin enough that each single corona light ray reaching the eye is scattered or diffracted by only one droplet. Of course, the whole corona is made by a great many droplets individually scattering the moonlight.
Sometimes as clouds pass over the moon the corona shrinks and swells as different sized droplets mould it. Small droplets make the largest coronae with aureoles a few moon diameters across. — Source