A user clicked a link in an email, and now the cursor is moving around...

When a user's cursor is moving on its own and unauthorized data transfer is occurring, the first step a technician should take is to Quarantine the workstation. This involves isolating the affected system from the network to prevent the spread of malware or unauthorized access to other parts of the network. Quarantining helps in containing the threat and provides a safe environment to investigate and remediate the issue without risking further contamination or data loss​​.