I need help. I'm using ubuntu 16.04.5 LTS. i wanna edit the crontab and i already login as root. when i run command "crontab -e", there is already a schedule that download file and execute. i think it's a trojan so i want to remove from crontab but everytime i change the crontab, the error message show "operation not permitted".
How to fix this problem and remove the injected script in my crontab?