Crystal Lake Community High School District 155’s computers were infected with ransomware on Friday, according to an email sent to parents on Monday afternoon.
Superintendent Steve Olson wrote in the email on Monday, which was shared by a parent with the Northwest Herald, that the district’s network monitoring systems detected the virus on a number of Windows computers on Friday.
“The district technology team immediately took district servers offline in order to protect student data and other sensitive information,” he wrote. “This team also worked tirelessly throughout the weekend to analyze our systems and verify that the attackers did not reach servers that house confidential information.”
After an analysis, the district said no student data, or other sensitive information, was accessed or compromised during the cyberattack, Olson wrote.
The virus did, however, disable several staff computers and laptops.
Staff received Chromebooks to continue with day-to-day classroom activities, Olson wrote.
“Until all Windows devices can be safely back online, we have asked staff and students to be flexible with their use of district technology in our buildings,” Olson wrote. “Because Chromebooks are generally not susceptible to viruses, your students can continue to use those to complete assignments.”