Close the PATH-hijack gap
A root cron job runs a script that calls backup-logs by bare name, with the world-writable /opt/maint/bin first on its PATH — a classic hijack setup.
Inspect the job, then lock down the writable directory.
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sudo) is student.
Hints
`cat /etc/cron.d/maint` shows /opt/maint/bin first on PATH; `ls -ld /opt/maint/bin` shows it is world-writable.
`sudo chmod 755 /opt/maint/bin` leaves only root able to write there.
Solution explanation
Root's job searched a world-writable directory first on its PATH and called a command by bare name — so any user could plant that command and have root run it. sudo chmod 755 /opt/maint/bin removed the write access that made the hijack possible. The sturdier long-term fix is to call programs by full path in privileged scripts and set an explicit PATH, but closing the directory shuts the door now.
Show solution
cd /home/student
cat /etc/cron.d/maint
ls -ld /opt/maint/bin
sudo chmod 755 /opt/maint/bin
ls -ld /opt/maint/bin