Boston College did the responsible thing of warning all graduates on their data base even though they are not certain on the extent of accounts accessed. 

http://www.msnbc.msn.com/id/7221456/

BOSTON - Boston College officials have warned 120,000 alumni that their personal information may have been stolen when an intruder hacked into a school computer containing the addresses and Social Security numbers of BC graduates.

Officials don't believe the hacker accessed the personal information, but instead planted a program that could be used to launch attacks on other machines. Still, amid rising concerns about identity theft, the school sent letters to its alumni. "As a precaution we have chosen to alert the entire database," Dunn said of the letters sent last Friday.