LFCS · Question #22
In case neither cron.allow nor cron.deny exist in /etc/, which of the following is true?
The correct answer is A. Without additional configuration, no users may have user specific crontabs. If neither /etc/cron.allow nor /etc/cron.deny files exist, the default behavior of the cron daemon is to prevent all non-root users from creating user-specific crontabs.
Question
Options
- AWithout additional configuration, no users may have user specific crontabs.
- BWithout additional configuration, all users may have user specific crontabs.
- CThe cron daemon will refuse to start and report missing files in the system's logfile.
- DWhen a user creates a user specific crontab the system administrator must approve it explicitly.
How the community answered
(23 responses)- A87% (20)
- B4% (1)
- C9% (2)
Why each option
If neither `/etc/cron.allow` nor `/etc/cron.deny` files exist, the default behavior of the `cron` daemon is to prevent all non-root users from creating user-specific `crontabs`.
When neither `/etc/cron.allow` nor `/etc/cron.deny` files are present, most `cron` implementations, like Vixie cron, default to a secure posture where only the root user is permitted to create `crontabs`, effectively denying all other users access to `crontab`.
This is incorrect; if both files are missing, the default is to deny all non-root users, not allow them.
The cron daemon will start normally; the absence of these files is a configuration state, not a fatal error preventing startup.
The `cron` system doesn't involve explicit administrative approval for user crontab creation but rather relies on allow/deny list configurations.
Concept tested: Cron access control default behavior
Source: https://linux.die.net/man/5/crontab
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