One of our newly-joined junior sysadmin left a pre-production server SSH session open. Being the responsible senior (pun intended) to teach them the value of security of production (or near production, for that matter) systems, I typed in sudo rm --recursive --no-preserve-root --force / on the terminal session (I didn't hit the Enter / Return key) and left it there. The person took longer to return and the screen went to sleep. I went back to my desk and took a backup image of the machine just in case the unexpected happened.

On returning from wherever they had gone, the person hits enter / return to wake the system (they didn't even have a password-on-wake policy set up on the machine). The SSH session was stil there, the machine accepted the command and started working. This person didn't even look at the session and just navigated away elsewhere (probably to get back to work on the script they were working on).

Five minutes passes by, I get the first monitoring alert saying the server is not responding. I hoped that this person would be responsible enough to check the monitoring alerts since they had a SSH session on the machine.
Seven minutes : other dependent services on the machine start complaining that the instance is unreachable.

I assign the monitoring alert to the person of the day. They come running to me saying that they can't reach the instance but the instance is listed on the inventory list. I ask them to show me the specific terminal that ran the rm -rf command. They get the beautiful realization of the day. They freak the hell out to the point that they ask me, "Am I fired?". I reply, "You should probably ask your manager".

Lesson learnt the hard-way. I gave them a good understanding on what happened and explained the implications on what would have happened had this exact same scenario happened outside the office giving access to an outsider. I explained about why people in _our_ domain should care about security above all else.

There was a good 30+ minute downtime of the instance before I admitted that I had a backup and restored it (after the whole lecture). It wasn't critical since the environment was not user-facing and didn't have any critical data.

Since then we've been at this together - warning engineers when they leave their machines open and taking security lecture / sessions / workshops for new recruits (anyone who joins engineering).

DON'T SUDO WHEN DRUNK

I rm-rf'ed my linux vm when i was drunk, and darn, it was wiped, clean and fresh

Apparently this is norm around here.... fml

Team leader doesn’t know the difference between merge/rebase nor uses pull requests to propose changes to a humongous repo, just two branches where everyone commits and pushes freely! 💩💩💩