Centos – Adding a directory to $PATH in CentOS

Just to be sure, have you tried running the command in a shell?

It could be something in the cron's shell config preventing ruby running. Verify your /etc/crontab looks similar to this (if you haven't customised it, this is RHEL default):

    [andy@]# cat /etc/crontab
    SHELL=/bin/bash
    PATH=/sbin:/bin:/usr/sbin:/usr/bin
    MAILTO=root
    HOME=/

    # run-parts
    01 * * * * root run-parts /etc/cron.hourly
    02 4 * * * root run-parts /etc/cron.daily
    22 4 * * 0 root run-parts /etc/cron.weekly
    42 4 1 * * root run-parts /etc/cron.monthly

You can also change your crontab to /5 * * * * to run the task every 5 minutes while testing (if plausible).

Do you have any other crons running atm?

As much as anything else it is a mindset.

By having your current directory as part of your path you are indeed increasing your risk. Just because a trojan program has been executed, does not mean that it will not do what one would expect of it. In other words, to use your ls example, the trojan program, unless it was designed by a dunce would indeed provide you the directory listing that you requested, so that unless you say the file sitting there, you would have no reason to expect that something had gone wrong (perhaps it would be smart and decide to remove itself from the directory list provided to lower the chance of detection even further).

For this to occur, it would mean that someone has already infiltrated a given system to the point that it could place files onto your file system. Thus you are already in a bad way, but there is still room for things to be made worse.

As a general practice, I do not place my current directory in my path on my linux/unix systems, and it is not a great hardship. When I write a program or script that I wish to use frequently, I place it into a folder that is in my path, and restrict the write permissions to said file.

Short answerer, will adding the current directory to your path lead to certain doom for a unprivileged user, likely no, but why take the chance?

For root, DO NOT DO IT.