The intrusion occurred at the Career Development Center on May 11, when someone gained access to the school's network from outside the university, Stanford general counsel Debra Zumwalt said. The university said that it began notifying people about the incident on Monday, contacting about 9,600 clients--mostly students--and 300 recruiters who registered at the office since 1996.
Client records included Social Security numbers and resumes, financial data, and government information, the university said. However, some recruiter records included credit card information.
When the network breach was detected, the center's computers were temporarily disabled and the incident was reported to the FBI field office in San Jose, Calif.
"Protection of confidential information is a high priority of Stanford," Zumwalt said in a statement. "Since this incident, we have been working to understand this breach of our system and ways to prevent a reoccurrence."
The notifications were made in accordance with the 2003, which requires companies to disclose incidents in which a California resident's confidential information has been jeopardized.
The break-in follows a similar incident at Virginia's George Mason University in January, in whichto the personal information, including Social Security numbers, of more than 30,000 students, faculty and staff. As a result of the attack, the university promised to change the manner in which it uses Social Security numbers to identify people, including striking the codes from its campus IDs.