A letter was posted on the university's website Thursday detailing the recently identified security breach affecting credit card purchases made at food outlets on the USC University Park and Health Sciences campuses.
"Credit card numbers were obtained illegally through a breach in a third-party software system used to process credit card transactions in some USC dining halls," Dan Stimmler, associate senior vice president at USC Auxiliary Services said in the letter.
The credit card numbers were obtained illegally between May 21 and June 21 and possibly earlier than that.
Locations included in the breach were Ronald Tutor Campus Center, Seeds, the Lab on Figueroa Street and Starbucks on the Health Sciences campus.
However, no personally identifiable information was compromised.
The Los Angeles Police Department and USC's Department of Public Safety was investigating.