About 6,000 University of Virginia faculty members have been warned that their personal details - including social security numbers and dates of birth - have been downloaded by hackers.
According to University officials, the hackers gained access to the records between May 2005 and April of this year.
Phil Higgins, senior partner at network systems provider Brookcourt Solutions, said a hack lasting two years was an embarrassment for the US college.
Higgins said, "Security system failures are becoming a fact of life in the modern IT environment, especially when IT managers rely on a single security technology to protect their systems, but a failure lasting two years? Come on."
Higgins said anti-virus software on desktops and firewalls placed around servers were not enough, and that organisations had to take a multi-layered approach to protecting their systems, including addressing internal threats.
Virginia is not alone in failing to quickly address security breaches of course. The biggest hack ever seen took place over about two years at the TJX group of clothing firms.