A hacker has infiltrated a University of California, Los Angeles database containing the personal information on 800,000 people, the school said on Tuesday, in one of the worst computer breaches ever at a U.S. university.

The hacker, who was seeking social security numbers, exploited a software flaw to crack the massive database, UCLA said in notices sent to all 800,000 potential victims, most of them current or former students and faculty members.

“My primary concern is to make sure this doesn’t happen again and to provide to the people whose data is stored in the database important information on how to minimize the risk of potential identity theft and fraud,” UCLA Acting Chancellor Norman Abrams said in a written release.

“We take our responsibility to safeguard personal information very seriously,” Abrams said.

The database contained names, social security numbers, dates of birth, home addresses and contact information that could be used by identity thieves. It is normally restricted to those whose jobs require them to have access.

Both the university and FBI were investigating the hacker, who first began trying to access the school’s computer systems more than a year ago, but declined to say whether a suspect had been identified.

“When UCLA discovered this activity on November 21, 2006, computer security staff immediately blocked all access to Social Security numbers and began an emergency investigation,” Abrams said in the letter.

“While UCLA currently utilizes sophisticated information security measures to protect this database, several measures that were already underway have been accelerated,” he said.

The university said it was not aware of any instance in which the personal information had been “misused” but was notifying all 800,000 people as a precaution.

University spokesman Phil Hampton said most of the rest of the names in the database were former students and faculty members and it was not used for fund-raising. He said that in some cases federal law required the university to maintain the information.

Computer security experts told the Los Angeles Times the sheer number of people exposed to the hacker made it one of the largest ever perpetrated against an American university.

In 2005, a database at UCLA’s cross-town rival USC containing 270,000 names was infiltrated. Earlier this year a U.S. Veterans Affairs laptop containing data on 26 million veterans and service members was stolen from a staffer’s home.

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