Attempting to have a user release information or perform an action on behalf of another is called

This could be what is called as a power of attorney. This is document gives a person or entity the authority to obtain information on your behalf or perform certain actions. This is usually used by individuals that are incapacitated or not present.

I believe the answer is User impersonation.

In general, impersonation is used to meet the security requirements of certain client/server applications. But if the process is done under unauthorized malware/virus, the process could potentially leak the user's information onto another party