I think that you need to define your context of "law" and "corruption". Do you mean "can law be bad?" or "can law be changed maliciously?" or "can law be changed without knowledge or consent of the lawmakers/holders?" It's all very complicated, and somewhat depends on the type of government.
Can a law in and of itself be evil? It can be, depending on your definition of evil. All the laws of North Korea are official laws. All laws of capital or corporal punishment were/are official laws. Laws against religion, life, or freedom are/were valid laws of their respective lands.
Can law be changed? Yes, all the time. Can law be changed unofficially? No. However, people can choose not to uphold, enforce, or interpret the law as it is written. This also happens all the time.