A student at the University of Delaware has been charged with hacking into the university's computers three times to improve her grades.
Darielle Insler allegedly used faculty passwords she obtained by impersonating her instructors in telephone calls to the university's personnel department, which unknowingly provided the information, authorities reported.
In one case, Ms Insler, 22, allegedly successfully guessed an instructor's password.
She declined to comment on the charges. According to police, Ms Insler was threatened with failing three classes in maths, science and literature. She changed her grades in two of the classes to the highest scores.
She is charged with identity theft, criminal impersonation, unauthorised access to a computer system and misuse of information on a computer system.
The university said employees should not have given Ms Insler faculty passwords over the phone. It said it had changed its procedures so that faculty are notified of passwords by email.
School officials declined to say if any additional disciplinary action would be taken against Ms Insler.
Faculty has pressed for strong action, but higher education officials said such cases were rare in US universities, which generally employ state-of-the-art computer security.