The attesting witness merely witnesses the signature of the testator, it is not necessary that he should know the contents of the Will.
The executor and also a legatee or a beneficiary named under the Will is competent to attest the Will. But any legacy or bequest given to a person who attests the Will, or to his wife or to her husband, or to any person claiming under either of them shall be null and void. The Will is void to the extent of share bequeathed to such person.
Section 67 of the Indian succession Act does not apply to Hindus. Hence the attesting Witness to the Will of a Hindu does not lose the legacy given to him by the Will.
Example: A left a will giving a legacy to B, who is an attesting witness. A afterwards executes a codicil confirming the legacy to B to which B was not an attesting witness. B is entitled to the legacy by virtue of the codicil.