University employees discovered unauthorised movies and games on the network on 2 January, according to a report in the Tucson Citizen.
The hacker, who authorities believe lives in France based on his or her IP address, could potentially have obtained university credit card details, information about transactions between university departments, and an unknown number of employees' Social Security numbers, according to press reports.
The university's Police Department and the FBI are investigating the incident, which left network service disrupted while PCs were cleaned and equipped with stronger prevention solutions, according to press reports.
A University of Arizona official could not immediately be reached for comment.
Hackings of large universities are nothing new. Just last month, the University of California, Los Angeles (UCLA) began alerting 800,000 people associated with the school that their personal information may have been compromised. UCLA officials discovered that hackers had been exploiting an undetected security hole in a database for more than a year.
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