Apple - Apple password verification showing weird characters

That looks like font corruption. I'd run the "standard toolkit"

• Fix permissions, Verify & if necessary Repair disk, using Disk Utility.

• Reset Home folder permissions & ACLs using OnyX - Maintenance tab/permissions, tick the box at the top then Execute.

• Update to [or re-apply if already up to date] 10.10.5 using the 10.10.5 combo update, not the delta from App Store.

The Font Database is corrupted, you can rebuild it. (NOTE: make backup before performing this)

sudo atsutil databases -remove

And then repair permissions:

sudo diskutil repairPermissions /

After it's finished restart your machine.