Police said the student was unlocking the door to her dorm room when she was approached by the subject, who grabbed her throat and left arm and held her against the door.
According to investigators, the suspect then rubbed her thigh and said something to the effect of, "This is how you like it."
The man turned her to face him and she pushed against him, at which point he left, saying that he would be back.
He may be a former Drew student and may have been a guest on campus at the time of the incident, police said.
Anyone with any information is asked to call CrimeStoppers at 973-COP-CALL (973-267-2255) or 1-800-Sheriff.
The investigation is being conducted by the Morris County Prosecutor's Office and Madison Police.
NEW YORK AND TRI-STATE AREA NEWS