If you have not saved the attributes before changing them, and also can't quit the Kernel, then you could launch a Subkernel and get the original attributes that way:

ClearAttributes[Log, Listable]

Attributes[Log]



  {NumericFunction, Protected}


First@ParallelEvaluate[Attributes[Log]]



  {Listable,NumericFunction,Protected}


How to restore function attributes to default
How to to restrict the translation (or rotation) in Z axis for a length (yellow line) and activate it after (blue line)? Using only logic bricks. 


