Nearly 200,000 electronic records at the University of Texas at Austin's business school have been illegally accessed, the school said.
It's the school's second major breach in three years.
The university said it learned late Friday that some Social Security numbers and possibly biographical material of students, alumni, faculty and staff might have been accessed.
The university has notified the state attorney general's office and established a call center and Web site for those whose records might have been breached.
"Our effort has been to help people whose information may have been exposed," university President William Powers Jr. said Sunday.
Officials discovered that some records at the McCombs School of Business had been breached as early April 11.
"We think the problem has been limited to McCombs," Powers said. "Since then, we've been working to make sure the entire system, not just McCombs, is secure."
Last year, a former UT student received five years probation and was ordered to pay $170,000 in restitution for hacking into the school's computer system in 2003 and accessing almost 40,000 government identification numbers.