School officials say the names, addresses and Social Security numbers for as many as 240,000 people connected to Western Illinois University were compromised by a hacker earlier this month.
Computer Support Services Director Mitch Davidson says someone accessed the WIU system that stores students' personal data on June fifth. The system also holds credit card information for anyone who used the Web to buy items from the school's bookstore or who stayed in the hotel in the student union.
Davidson says the hacker was in the system for a short period of time and officials don't know if any records were viewed or copied.
WIU spokesman John Maguire says the university's Office of Public Safety is also investigating. The school plans to begin mailing letters to those affected on Monday.