[SOLVED] "/" directory permissions changed somehow...

[W_T]

I've just realized that my "/" directory permissions have been changed to drwxrwxrwx somehow. It has been discovered by me when I was checking ufw status - there was an information that my "/" directory is group and world writable.
I know how to revert it to the "normal" state (drwxr-xr-x), but my question is: how it happened in the first place?
I'm using LM 18.1 Cinnamon 64-bit.

[Cosmo.]

Short answer: Not on its own.

Did you play anywhere with the chmod command?

[W_T]

I didn't use chmod since last install.
I've found similar issues:
viewtopic.php?t=224238
viewtopic.php?t=162869
But I have still no clue regarding the cause.

[Cosmo.]

There is no hint in the linked threads, why this had happened there. Fact is: This doesn't happen on its own. It did never happen on any of my systems in years. And there are not really many complaints, what would be expected, if this would a kind of bug and happen repeatedly. So there must be a special cause on your side, but from the distant impossible to analyze, if chmod (or any equivalent) has never been used.

Only a guess: Did you ever created a network share for the complete file system?

[sgtor]

How interesting.

I came here to post the exact same question. Very same circumstances too, I tried to add a firewall rule with gufw and got an error which led me to / with 777 permissions. I too have changed it back to 755. I didn't change it to 777 myself ever. I ran tiger and it said kernoops has / as a home directory. A google search came up with a post that it is normal for tiger to say that.

That's as far as I am atm.

LM 18.1 Mate

[sgtor]

A small update. I've just discovered that ufw is turning itself off and iptables -L shows no rules so I think I have a rootkit on my system.
I've been thinking about switching to LMDE anyway so I'll just reinstall.

Looking back I'm pretty sure I messed something up since I was doing a lot of experimenting knowing that it was a temp system and I would reinstall anyway. I'll be leaving the experimenting to a virtual machine after I get LMDE installed though.

[W_T]

Only a guess: Did you ever created a network share for the complete file system?

I'm not sharing, but rather accessing Windows machine shares from this one.
I don't recall performing any administrative tasks which would require dealing with directory permissions.
I was just playing with some live-session distros, audio apps and JACK. Regarding ufw: I've only enabled it and allowed incomming connections through BitTorrent port.
Strange thing...

[Cosmo.]

I was just playing with some live-session distros...

This is the only point in the list, where I could possibly imagine a relationship to your problem - depending what you played and if the hard drive was somehow involved.

[W_T]

Cosmo, Your assumption was correct.
Running the live session of AV Linux (isotester-avl64-2016.8.30 in this case) was the cause of it. I have checked twice with the same result every time. I didn't even touch anything within the file system during the live session - just run it and then reboot back to Mint.
Later I have found out that permissions altering is a standard and documented feature of AV Linux live session.
For me the issue is solved. Thanks for the help.