The Montgomery Public School System released more information Friday on the "worm" that infected its computer servers and forced teachers and administrators to stop using their computers for days.
MPS Director of Technology Support Don Dove said the school system's IT department detected "suspicious activity on a data center server" on Saturday and determined it to be "malicious".
A decision was made to isolate the data center and shut down key servers, Dove said in a statement released by the school system.
"Working in an isolated environment, server administrators identified the malicious activity as a new strain of a bitcoin-mining worm," according to Dove. "The worm infiltrated our data center through an older, vulnerable Microsoft Exchange server. The IT staff eradicated the worm and sent Microsoft data logs, allowing them to update their security definitions."
Dove said IT was already working to decommission the vulnerable server and has since finished that process.
"The security of the MPS data center has been fully restored," he added. "At no point during this process was MPS student or staff data at risk."