Hackers attacked computer servers of a California university and may have gained access to the personal information of 59,000 people affiliated with the school , a university spokesman said on Monday. California State University, Chico in northern California is alerting students, former students, prospective students and faculty that their personal information, including Social Security numbers, may have been compromised in the attack three weeks ago, said spokesman Joe Wills.

"It looked like it was illegal access to do some, perhaps, some downloading of files," Wills said. "In investigating it we realized the hackers had some access to a great deal of personal information."

"We have no indication that the hackers used the information ... But we can't say for sure," Wills said. "My understanding is that to this point we haven't had any success in figuring out who did it."

The school will continue probing the attack on its servers, Wills said.