Forty computers in the UW-Madison Department of Chemistry were hacked over the course of roughly 18 months, possibly exposing the names and Social Security numbers of 2,920 people on campus.
UW-Madison authorities sent a letter Oct. 12 to faculty, staff and students who were affected, apologizing for the security breach and promising that new security tools are being put in place.
The computers were used as part of an underground network distributing music, movies, television shows and commercial software.
"There is no evidence that the unauthorized individuals were aware of your personal data on the compromised computers or that it has been retrieved or misused," said Department of Chemistry Chairman Robert Hamers and Chief Information Officer Ronald Kraemer in the letter.
University officials learned of the breach on Aug. 31. During the course of an investigation, they found that the computers were hacked mostly over the past 18 months, but the earliest incident happened in December 2001, according to the letter.
Some of the compromised computers contained the nearly 3,000 names and Social Security numbers, which were used for official university business.
The identities of those who obtained unauthorized access remain unknown, the letter said.
Since learning of the issue, university officials said they have taken steps to prevent another hacking attack.
Departmental computers were scanned to remove or encrypt personal data, network monitoring has increased, and all department operations now reside behind a restrictive firewall, according to the letter.