What are the runtime permissions of a cron job?

You can specify a user in the system crontab entries like so:

# For details see man 4 crontabs # Example of job definition: .---------------- minute (0 - 59) | .------------- hour (0 - 23) | | .---------- day of month (1 - 31) | | | .------- month (1 - 12) OR jan,feb,mar,apr ... | | | | .---- day of week (0 - 6) (Sunday=0 or 7) OR sun,mon,tue,wed,thu,fri,sat | | | | | * * * * * user-name command to be executed 

The 6th argument can be a username. Additionally you can put scripts in the /etc/cron.d directory. The scripts take the same form as the crontab entries described above, for example:

# /etc/cron.d/clamav-update ## Adjust this line... MAILTO=root ## It is ok to execute it as root; freshclam drops privileges and becomes ## user 'clamav' as soon as possible 0 */3 * * * root /usr/share/clamav/freshclam-sleep 

You can put scripts in these directories, but they're meant to be run as root:

• cron.daily
• cron.hourly
• cron.weekly
• cron.monthly

Finally you can create user based crontab entries by running this command as a given user:

$ crontab -e 

These entries are stored in files with the same name as the user in this directory, /var/spool/cron/:

$ sudo ls -l /var/spool/cron/ -rw------- 1 saml root 0 Jun 6 06:43 saml 

Yes, however, jobs that are added manually to the systems crontab (edit /etc/crontab) will be run with absolute permissions (ie: run as root) unless you specify another user.