The university was alerted of the breach Monday and later learned the attacker rerouted the payments by accessing the victims' university login information, ISU Chief of Staff Jay Groves told The Pantagraph.
Those affected have since had the proper amounts credited to their accounts and in order to protect the integrity of other accounts the university has temporarily suspended the ability to modify bank routing information for direct deposits online.
A total of $50,000 was involved in the incident and the university is working with the Federal Bureau of Investigation and Illinois State Police in its investigation.
Faculty, staff and students have been instructed to check their accounts for fraudulent activity.
Groves said there have been five other universities around the country where similar incidents have occurred.